A Guide to the Role of Standards in Geospatial Information Management

Edition 3.0.0:2022-01-01,
unggim-feedback@opengeospatial.org

Summary

The purpose of this Guide is to promote the recommendations regarding the use of standards for geospatial information management. The Guide complements Strategic Pathway 6 on Standards (SP6) of the Integrated Geospatial Information Framework (IGIF) Implementation Guide, providing specific guidance and options to be taken by countries when implementing the IGIF.This Guide and the IGIF have been developed through extensive consultations with experts from around the world working under the auspices of the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM).

This Guide provides detailed insights on the standards and good practices necessary to establish and maintain geospatial information management systems that are compatible and interoperable with other systems within and across organizations. The Guide also underscores the importance of standards in facilitating the application of the FAIR (Findable, Accessible, Interoperable, and Reusable) data principles - promoting improved policymaking, decision making and government effectiveness in addressing key social, economic, and environmental topics, including attainment of Sustainable Development Goals.

The Guide addresses different target audiences and the roles they play in performing implementations of standards, while raising awareness of the benefits and costs of engagement:

Decision makers - who need guidance and coordination to understand the benefits of standards and the importance of setting strategic goals to achieve increasing levels of geospatial maturity.
Developers of interoperable solutions - who need working knowledge about what standards are needed and applicable in different cases, as well as methods to access the standards to take the essential steps for implementing geospatial standards and interoperable solutions.
Standards users - who must understand the importance of adhering to standards and to provide feedback into the ongoing use of the implemented standards.
Practitioners in the public and private sector and civil society - who need to know the benefits of working with standardized data, how and why things work the way they do, and can share experiences and standards success stories with others.

While this Guide provides guidance on the benefits of implementing current, broadly implemented standards, it also provides insight on the importance of managing change. Standards must continuously adapt to changes in technology and other developments. On a regular basis, the UN-GGIM reviews and publishes a five to ten year vision on future trends in geospatial information management that informs readers of upcoming developments. In the most recent version, the top geospatial industry drivers predicted to have the greatest impact on geospatial information management over the next five to ten years were identified and grouped into five categories: rise of new data sources & analytical methods; technological advancements; evolution of user requirements; industry structural shift; and legislative environment. In terms of the IGIF Strategic Pathways, these drivers are expected to have a significant impact on standardization needs.

This Guide represents the work of individuals around the world who contributed their time and expertise in global cooperation, with the encouragement of their home nations and employers, in some cases on a voluntary basis. As a reader of this document, we invite your participation and contributions as your encouragement plays a crucial role in bringing your nation’s and employer’s perspectives and insights to the geospatial community. This Guide is intended to be a living document, regularly reviewed and updated. The authors invite you to send your feedback, suggestions, and contributions to unggim-feedback@opengeospatial.org to help us improve the utility of this Guide.

Introduction

Geographic information describes phenomena on, above or below the Earth’s surface, including naturally occurring phenomena (e.g., rivers, rock formations, coastlines), human-made phenomena (e.g., dams, buildings, radio towers, roads), social phenomena (e.g., political boundaries, electoral districts, population distribution) and transient phenomena (e.g., weather systems). Geographic information is also referred to as geospatial information, geodata, geoinformation, location-based data, or spatial information. Standards facilitate the integration of all kinds of geographic information to enable more effective policies and decision-making. They form part of the architecture by which such information can be discovered, collected, published, shared, stored, combined, and applied. Standards also enable collaborative geospatial information management across organizations and levels of government.

Standards can serve as non-binding policy components to help advance a legal and policy framework for geospatial information management. Adoption of standards by key stakeholders responsible for geospatial information management will have a broad impact across the geospatial ecosystem of a nation, organization, or information community. Standards can be made binding by including them into requests for proposals (RFPs), tenders or contracts. However, standards should be implemented according to the respective needs of a country, organization, or information community.

This Guide complements the IGIF SP6. The IGIF provides a basis and guide for developing, integrating, strengthening, and maximizing geospatial information management and related resources in all countries. In SP6, the focus is on the adoption of standards and compliance mechanisms for enabling data and technology interoperability to deliver integrated geospatial information and to create location-based knowledge. The purpose of this Guide is to promote the effective use of standards and to help users of standards answer the question, "Where do I start?". It has a section for each of the six actions recommended for the initial and early stages of developing and strengthening geospatial information management arrangements in a country, organization, or information community (see Figure I.1).

Figure I.1 Actions and tools designed to assist countries to establish good practice standards and compliance mechanisms (Adapted from IGIF SP6)

Furthermore, use cases (case studies), an integral part of this Guide, are introduced in each section of the document, with an expanded list of case studies also provided as an Appendix. Specific guidance and options are provided for those who want to implement standards adoption and compliance as part of an IGIF.

Even though the IGIF SP6 aims to guide country-specific action plans for standards adoption and compliance in the context of national geospatial information management, this Guide is also useful for other organizations, such as state and provincial governments, private sector, and non-profit organizations. This Guide will help them to understand how their data, services and systems can be seamlessly integrated with national geospatial information and how their products and offerings can achieve the necessary flexibility to innovate and rapidly mobilize new technologies and data sources.

The target audience for this Guide comprises four groups representing the different roles they play in standardization. Each of the groups can be linked to one of the four Elements of Standards in the IGIF/SP6, illustrated in Table I.1. This Guide was prepared with the aim to be understandable by those who are relatively new to the topic of geospatial standards, as well as those proficient in the use of standards. At the same time, this Guide provides guidance to both high-level policy and decision-makers, as well as implementers of standards.

Table I.1 The four groups of the target audience for this Guide and their relation to the IGIF SP6 Elements of Standards.
Roles	Link to IGIF/SP6 Element	Required level of understanding standards	Activities	Relation to this Standards Guide
Decision makers	Governance and Policy	Can recognize the benefits of standards, in reaching long-term goals	- Set government policy framework- Allocate funding	Secondary target audience
Developers of interoperable solutions	Technology andData Interoperability	Can implement standards, Can develop & revise standards	- Ensure design meets national needs and challenges- Participate in standards development	Main target audience
Standards users	Compliance Testing and Certification	Can interpret & use standards	- Participate by expressing needs- Implement internal policy to align with endorsed standards	Target audience
Practitioners in the public and private sector, and civil society	Community of Practice (CoP)	Can discover & use standards as good practice	- Identify needs for standards contributing to the Sustainable Development Goals (SDGs)- Participate in standards development, adoption, and implementation	Target audience

Decision makers are responsible for the governance framework and policy environment that support standards adoption and compliance. They also provide the resources and allocate funding. Decision makers therefore want to understand how the benefits of standards adoption and compliance can be maximized to achieve their strategic goals. This Guide provides examples from a number of countries, information communities or organizations; guidance on how to develop a common framework of national data and technology standards; and guidance on how national requirements can be represented and addressed in the activities of international Standards Development Organizations (SDO). Decision makers can use these examples to guide action plans for achieving optimal outcomes and benefits. After reading the respective section in the Guide, a decision maker will be able to:

Direction setting: Understand the benefits of standards and the importance of setting strategic goals to achieve increasing levels of geospatial maturity.
Understanding needs: Understand which standards are available to assess and address an organization’s needs based on geospatial maturity level or tier.
Planning for change: Understand how other nations or organizations have implemented and used standards to meet their needs.
Taking action: Understand the level of maturity of the nation and/or organization and thereby the level of complexity and the potential work that needs to be done during the implementation phase.
Ongoing management: Authorize and resource a standards maintenance process essential for maintaining an effective national geospatial information management and sharing environment.
Achieving outcomes: Understand the importance of how standards will improve sharing and use of geospatial information and optimize geospatial information management

Developers of interoperable solutions are the primary target audience for this Guide. They develop and implement technologies so that different systems and diverse data types can work together seamlessly. They may also be involved in the development of standards or profiles that meet the specific needs of their countries or organizations. This Guide provides them with information about the different types of standards, how they facilitate interoperability, how to access standards and how they have been implemented in other countries, information communities and organizations. Developers of interoperable solutions can use this Guide to plan and design their own implementation or development of standards to ensure that they meet the needs and address the challenges of their countries or organizations. After reading the respective section in this Guide, a developer of interoperability will be able to:

Direction setting: Identify the types of standards required for increasing levels of capability and scale of collaboration and understand the role of SDOs and how to participate in standards development.
Understanding needs: Understand which standards are available to assess and address an organization’s needs based on geospatial maturity level or tier, and understand how standards are evolving along with changing needs and technologies.
Planning for change: Understand the importance of considering and implementing standards as part of the systems development lifecycle, and the importance of contributing to and providing feedback to the development of standards through direct participation and provision of feedback.
Taking action: Understand details about what standards are needed and applicable in different cases, how to access the standards, and how to take the essential steps to implement those standards.
Ongoing management: Understand how to remain current with advancements in standards through periodic review with standards bodies and communities of practice.
Achieving outcomes: Understand use cases to apply rapid mobilization of new sources of data and technologies and avoid lock-in to specific technology providers.

Standards users evaluate and select standards or standards-based products for implementation in their countries or organizations, with the goal of achieving national or organizational goals. They need to understand how a standard achieves interoperability and whether a standards-based product complies and/or is certified to comply with a standard. They want to know the standardization target for a specific standard (e.g., web service or metadata) and the kind of interoperability that can be achieved (e.g., system, structural, syntactic, or semantic). This Guide provides them with information about the different types of standards, how they facilitate interoperability and how compliance to standards is tested and certified. The Guide helps to inform the evaluation approach followed by a standards user to make sure that selected standards or standards-based products meet the needs and address the challenges of their countries, organizations, or information communities. Each section provides standards users with specific insight into an effective implementation strategy:

Direction Setting: Understand the different types of standards and how they contribute to interoperability and generate benefits.
Understanding Needs: Understand which standards are available to assess and address an organization’s needs based on geospatial maturity level or tier, and understanding how standards are evolving along with changing needs and technologies.
Planning for change: Understand the types of business needs that may be supported through the implementation of standards, advocating for the adoption of standards to facilitate interoperability and other efficiencies, and understand the importance of considering and implementing standards as part of the systems development lifecycle, and the importance of contributing to and providing feedback to the development of standards through direct participation and provision of feedback.
Taking action: Match the standards required to fulfill their needs to a given maturity level.
Ongoing management: Discuss, identify, and submit requirements for standards to address interoperability issues through standards bodies at the organizational, national, and international levels.
Achieving outcomes: Understand requirements for improved uptake of geospatial information across government and with the private sector and citizens; and creating efficiencies in geospatial data production and lifecycle management; saving effort, time, and cost in reusing and repurposing data.

Practitioners in the public and private sector and civil society are often represented in different communities of practice, groups of people with a shared interest in standards who actively participate in the development, adoption, implementation and/or use of standards. A community realizes the benefits of standards and interoperability by sharing and leveraging proven standards-based good practices and training material specific to their community’s needs. A Community of Practice (CoP) can also provide commonality across diverse uses and levels of operation, and help promote consistent, sharable training and educational programs. This Guide provides communities of practice with an overview of standards and standardization and suggests domain and technology trends expected to be standardized in the future. CoPs can use this Guide to inform and plan contributions to standards development, adoption and implementation of standards, and development of training material and educational programs. It can also serve to identify a community’s standardization needs that are not yet addressed. After reading the respective section in this Guide, members of a CoP will be able to:

Direction setting: Understand the different types of standards and how they contribute to interoperability and generate benefits.
Understanding needs: Understand which standards are available to assess and address an organization’s needs based on geospatial maturity level or tier.
Planning for change: Understand how they can play a role in the identification of opportunities for standardization in the context of their domain, act as advocates to engage related communities of practice to facilitate alignment and interoperability at various levels.
Taking action: Understand the standards and provide feedback into the ongoing development of the implemented standards.
Ongoing management: Understand how they can share experiences and standards success stories with others.
Achieving outcomes: Understand the benefit realization and compliance of standards with the development of indicators to assess, monitor and evaluate as part of an internal/external auditing exercise.

1. Direction Setting

The purpose of this section is enabling the reader to:
* Understand the benefits of standards and the importance of setting strategic goals to achieve increasing levels of geospatial maturity.
* Identify the types of standards required for increasing levels of capability and scale of collaboration.
* Understand the role of standards development organizations (SDOs) and how to participate in standards development.
* Understand the different types of standards and how they contribute to interoperability, and examples of benefits.

Standards Awareness

When undertaking a leadership role on geospatial standards, it is important to understand the practical use of standards and to raise awareness of the benefits of moving towards a standards-based approach for geospatial data management at all levels of government, the private sector and academia. ^[1] When it comes to the implementation of standards, benefits include:

Reducing cost over the lifecycle of a system or systems.
Ensuring the ability to share data when appropriate, with respect for privacy issues.
Enabling interoperability among systems.
Enabling interoperable sharing and operations.
Enabling innovation by facilitating rapid mobilization of new technologies and data sources.
Supporting disconnected or local operations.

Interoperability is the ability to access, exchange, integrate and cooperatively use data in a coordinated manner, within and across organizational, regional, and national boundaries.^[2] As described in IGIF SP6, technology and data interoperability enables different technologies, systems, and geospatial data to work together seamlessly, and provides the flexibility to rapidly mobilize newer technologies and data sources.

What are Standards and Why are They Important?

A standard is a documented agreement between provider and consumers, established by consensus, that provides rules, guidelines, or characteristics ensuring materials, products, and services are fit for purpose. Behind the scenes, standards make everyday life work. They may establish size or shape or capacity of a product, process, or system. They can specify performance of products or personnel. They can also define terms so that there is no misunderstanding among those using the standard.

Standards Save Time, Money, and Lives

Figure 1.1 Aftermath of the 1904 Great Baltimore Fire (source: Wikipedia)

In 1904, much of the City of Baltimore in the United States was destroyed by a massive fire. Firefighters from hundreds of kilometers away were sent to assist Baltimore firefighters during the height of the blaze. They could do little to help because the fire hose size and threads used by different responders were not standardized for compatibility with Baltimore fire hydrants ^[3]. The resultant inability to connect hoses to fire hydrants turned hundreds of firefighters into spectators. This analogy rings true not just in respect of the need to share geospatial information, such as disaster imagery, during a crisis but throughout all implementations of geospatial technologies. Standards make uniformity, compatibility, and interoperability possible for electronic devices, software applications, and processes in all sectors of a global economy.

Without standards, the ability to connect systems, data, people, hardware, software, and procedures becomes difficult and inefficient. Loss of time, assets and lives is inevitable.

A recent example of the value of standards was brought to the surface by the COVID-19 pandemic. Addresses provide one of the most common and unambiguous ways to identify and locate objects, and assist services such as postal delivery, emergency response, marketing, mapping, utility planning and land administration. Addresses and address data turned out to be crucial in the fight against COVID-19 because they enabled contact tracing and identification of cluster outbreaks. Non-standardized addresses significantly hinder the response to COVID-19. The multi-part International Organization for Standardization (ISO) 19160 Addressing Standard supports a variety of stakeholders so that accurate and reliable address data can be made available. The different parts of ISO 19160 cover topics such as terminology and a conceptual data model for addressing; good practices for address assignment and maintenance; quality of address data; and international postal addressing (jointly developed with the Universal Postal Union).

The Case for Open Standards

Open standards facilitate interoperability and data exchange among different products or services intended for widespread adoption. Standards and specifications define requirements to ensure that products and data are consistent in accuracy, structure, format, style, and content. ^[4] Standards development is a process that requires consensus among stakeholders. Open standards are a central element in the growing trend towards effective government.

Open international standards are voluntary consensus-driven standards published by the SDOs. Open standards ^[5] are developed, approved, and maintained via a collaborative and consensus-driven process and made available to the general public. These standards are aimed at achieving legal, data, semantic and/or technical interoperability. Furthermore, open standards offer users the opportunity to have a voice in building and learning about the standards. Apart from standards, the SDOs offer other types of open documents and services, such as specifications and reports, to respond to urgent market needs or to address work still under technical development.

The main focus of the IGIF SP6 and this Guide is on open international geospatial standards. However, other means of information sharing that may lead to or supplement standards are also described in this subsection:

Specifications generally offer an interoperability solution similar to that of standards, but are not necessarily developed in the same voluntary, consensus-based process. Specifications may precede or contribute to the body of knowledge for new open standards, thus serving a meaningful role in furthering innovation in the geospatial industry. ^[6] In the case of the OGC, output from the OGC Innovation Program initiatives may result in draft specifications for consideration for development as a standard. Further, open standards or specifications developed externally to the OGC may submitted to the OGC to become formally endorsed as OGC community standards.^[7]

Based on international standards, profiles may be established and endorsed by governance bodies to meet the specific needs of their country or organization. Metadata profiles, such as the INSPIRE dataset and service metadata, and the _Latin American Metadata Profile LAMP version 2 (LAMPv2) are examples of profiles based on international standards.

Good practices describe how an open standard is applied against scenarios or define a profile that tailors it to the requirements of a specific community. Good practices (also referred to as best or proven practices) often highlight the practical use of one or more standards and specifications or address particular use cases. They may relate to implementing tools and techniques, emerging technologies and standards, or extensions/profiles for specific application domains. ^[8]

Over time and with broad adoption, a specification may be so widely used that the community considers it a de facto standard for a given application, even if it was not assigned an official status by a governance body. Developers should be aware that some de facto standards require proprietary solutions to be licensed in order to implement them. De facto standards should balance interoperability, access, and use requirements and be used in parallel with open international or national standards when possible.^[9]

Closed standards or specifications carry risks that may pose hidden challenges such as delays and costs of expanding or adapting data and software tools to work with other resources, software, or organizations. Organizations should be aware of the potential risk to interoperability of closed standards or specifications and consider these risks on balance with the benefits. Open standards and specifications, on the other hand, help organizations best balance their needs while minimizing business and technology risks.

In an ever-changing world, open standards help assure that organizations can more quickly take advantage of new geospatial information sources and new technology tools. International standards developed and maintained by the consensus processes of recognized SDOs help avoid risk by broadly addressing and managing community requirements for interoperability, access, and use.

The Benefits of Open Geospatial Standards

Geospatial information, technologies, and standards help enable and improve the sharing, integration, and application of geospatial information for decision making. While national governments can make proactive policy choices to maximize benefits, other jurisdictions and enterprises must align with this policy to achieve mutually optimal outcomes.

A multi-national response to a regional disaster is one example where having clear policy on the sharing of geospatial information is critically important. The shaping of appropriate geospatial policy is beyond the mandate of this Guide (See IGIF SP2), but it must be addressed. For without a suitable policy framework the standards-based approaches described in this Guide will be of limited value.

The remainder of this Guide seeks to answer the following questions directly related to the role of standards in geospatial information management:

What are the common standards adopted by organizations worldwide?
Which of these standards are appropriate for geospatial information management in the context of the UN initiative on Global Geospatial Information Management?
What are the appropriate geospatial standards for an organization’s needs?

In addition to these questions the overall value proposition associated with open standards should be considered by all stakeholders. The fundamental questions include quantifying the benefits, examining the reduction of related risks, as well as the potential for improved productivity and new opportunities.

Examples of Quantitative Benefits

Open standards facilitate increased return on geospatial investment through a host of mechanisms. Return on investment may be realized through direct means such as improved efficiency, from saved time and effort, or through the ability to rapidly mobilize new capabilities. The following examples demonstrate the monetary benefits of standardization:

The German Institute for Standardization (DIN) estimated benefits of 17 billion euros to the German economy in 2010: "Standards promote worldwide trade, encouraging rationalization, quality assurance and environmental protection, as well as improving security and communication. Standards have a greater effect on economic growth than patents or licenses." ^[10]
The Joint Research Centre of the European Union collaborated with the Universitat Politècnica de Catalunya (Spain) in concluding that the establishment of the Spatial Data Infrastructure (SDI) of Catalonia — based on open geospatial standards — generated significant internal efficiency benefits as well as benefits of more effective service delivery. They quantified these benefits and estimated that the value exceeded four year’s investment in just over six months. ^[11]
Of the projects considered in a NASA Geospatial Interoperability Return on Investment Study, the project that adopted and implemented geospatial interoperability standards had a risk-adjusted ROI of 119.0%. This ROI is a "Savings to Investment" ratio. This can be interpreted as for every $1.00 spent on investment, $1.19 is saved on Operations and Maintenance costs. Overall, the project that adopted and implemented geospatial interoperability standards saved 26.2% compared to the project that relied upon a proprietary standard. One way to interpret this result is that for every $4.00 spent on projects based on proprietary platforms, the same value could be achieved with $3.00 if the project were based on open standards. ^[12]
New Zealand SDI Benefits: Spatial Information in the New Zealand Economy - Realizing Productivity Gains is a report commissioned by Land Information New Zealand, the Department of Conservation, and the Ministry of Economic Development. It provides robust economic analysis that quantifies the contribution spatial information makes to the New Zealand economy, as well as opportunities for this contribution to grow. The report concludes that use and re-use of spatial information is estimated to have added $1.2 billion in productivity related benefits to the New Zealand economy in 2008. ^[13]
The Global Geospatial Industry Outlook (2019), published by Geospatial Media and Communications, valued the global geospatial industry at an estimated US$ 339.0 billion in 2018. The cumulative geospatial industry is projected to reach US$ 439.2 billion by 2020, growing at a compound annual growth rate of 13.8%. This growth acceleration can be accredited to continuous technology advancements in the industry, democratization of geospatial information riding on integration with advancements in digital technologies and resultant innovative business models. Adopting open standards is considered to be important for the way forward and for realizing the full potential of geospatial technologies.
In 2019, the Singapore government announced a Marine Spatial Data Infrastructure (MSDI) called " GeoSpace-Sea". Focused on data harmonization and interoperability standards, GeoSpace-Sea is designed to bridge the land/sea information gap and enable interdisciplinary marine coastal applications for the Singapore government. The establishment of a national MSDI will help provide environmental, social, and economic benefits to Singapore. For instance, the maritime industry, which contributes 7% of Singapore’s Gross Domestic Product (GDP), and the aquaculture industry will benefit from GeoSpace-Sea through increased efficiency, safety, and sustainability.

Key Types of Geospatial Standards

There are several different ways in which standards for geographic information can be categorized or characterized. The IGIF SP 6 refers to three general types of standards:

Domain-specific standards
General-purpose standards for geospatial information and technology specifically
General-purpose standards for information technologies and the internet generally.

Examples of standards for each of these types are found in Sections 2 and 4 of this Guide.

Some standards serve as general-purpose IT standards. For example, the Unified Modeling Language (UML), developed and published by the Object Management Group (OMG) and ISO/IEC JTC 1, can be used for "specifying, visualizing, constructing, and documenting the artifacts of software systems, and for business modeling". It is not specific to geospatial information and technologies. _ISO 19103, is a profile ^[14] of UML for the special case of describing geographic information. It is not specific to any domain or context and therefore also has a general purpose in the context of geospatial information and technologies. The general-purpose standards are also referred to as "foundational" standards because they form the technological basis for geospatial information exchange (see Figure 1.2).

Other standards describe geographic information related to a specific domain or context. Standards, such as the Open Geospatial Consortium (OGC) Groundwater Markup Language (GroundwaterML), _ISO 19160-1 Addressing — Part 1: Conceptual model, and _ISO 19152 Geographic information - Land Administration Domain Model (LADM) make use of the general-purpose _ISO 19103 Geographic information — Conceptual schema language to describe geographic information related to ground water, addressing and land administration respectively.

Figure 1.2 Characterization of general-purpose IT and geospatial standards, and domain-specific geospatial standards.

Geospatial standards can be further characterized based on one of three standardization targets^[15]:

Information (or content) standards
Service or interface standards
Procedural standards.

A specific standard is not necessarily aimed at a single standardization target. Sometimes information, services and procedures are grouped into a single standard for a specific domain. For example, ISO 19147 defines both transfer node information relevant for travel planning and modelling of interoperable transport systems, as well as a set of services related to transfer nodes.

Therefore, these characterizations are important when deciding which standard to use and are described in more detail below:

Information standards address heterogeneity at the semantic, structural, and syntactic level, i.e., they standardize the meaning of information (e.g., by defining concepts), how it is structured (e.g., through a conceptual model) and how it is encoded (e.g., a standardized digital encoding). Examples include OGC GroundwaterML, ISO 19115-1, Geographic information — Metadata — Part 1: Fundamentals and ISO 19160-1.

Figure 1.3 International cooperation on Arctic issues through OGC / ISO standards-based SDI and Portal

Service or interface standards define the rules for interacting with services and components in order to discover, access or process geographic information. Examples include the OGC Web Mapping Service (WMS) (also ISO 19128), OGC Web Feature Service (WFS) (also ISO 19142) and ISO 19132. Ideally, when standards are implemented in products or online services the resulting components work together seamlessly.

Procedural standards describe an ordered series of steps to accomplish a specific task. Examples include ISO/TS 19158, and _ISO 19135-1 Geographic Information - Procedures for item registration - Part 1: Fundamentals. Together, these standards allow different systems and applications to communicate and work together.

When selecting Interoperability standards, one needs to know which kind of interoperability ^[16] can be achieved by its implementation.

System interoperability is achieved if hardware, operating systems, and communication systems are able to communicate and work together, e.g. by standards such as IETF IPv6 and _IEEE 802.

Syntactic interoperability is achieved if different systems, applications, or services can exchange information via a common encoding, such as GeoJSON or the shapefile format.

Structural interoperability is achieved if systems, applications, or services can exchange information through a common conceptual model or the mapping from one model to another. This addresses heterogeneity in structure, e.g., a street can be represented as an object of the type 'Street' or by a generic geospatial object whose attribute (or tag or property) has the value 'street'.

Semantic interoperability is achieved when the differences in language, cultural and domain meanings between concepts and data representing reality are eliminated. These differences arise from the various perspectives and contexts from which real-world phenomena are abstracted. Between organizations, and even within the same organization, the terminology for a particular phenomenon may have many meanings and contexts. For example, depending on the context, a "bridge" can be an element of a road infrastructure, a platform of a ship, an obstacle in marine navigation, or a point of interest for tourists. Another example, a 'tower' can be a communication facility, a navigation landmark, and an aeronautical obstacle.

Semantics, in the context of this Guide, refers to the meaning of words, terms and concepts related to geospatial information. Semantic interoperability is an important part of standardization at national, international, and local levels. For information to flow among jurisdictions and organizations, it is essential that all parties agree on the meaning or intent of what the information represents. Through the semantic mediation process, national data can be combined with common meanings to address regional topics that transcend national boundaries.

How are Standards Implemented?

Depending on how they are used, standards can be grouped into meta and application (or instance) level standards:

Meta level standards will typically not be implemented at the country level yet are required for the development of other standards. It is important to know that these standards exist and understand their role in standardization. Examples include ISO 19104, and _ISO 19105,

Figure 1.4 Using OGC WaterML and OGC/ISO application-level web services standards, New Zealand created an integrated national water resource system from 16 separate regional catchment authorities. www.ogc.org/blog/3285

Application level standards are directly implementable, such as metadata standards (e.g., ISO 19115-1), ontologies for a specific domain or implementation (e.g., _OGC WaterML or _ISO 19160-1) or service specifications (e.g. _OGC WMS and _OGC WFS). Countries often develop their own profiles (specializations) of international application-level standards (e.g., the Infrastructure for Spatial Information in the European Community (INSPIRE) Metadata),
Instance level standards refer to the implementations of standardized data, services, or procedures. Examples would be the standardized geospatial datasets that are made available as part of a national SDI.

SDOs for Geospatial Information

The majority of international standards are developed in SDOs that use a consensus process guided by documented, repeatable and well proven policies and procedures. This helps ensure that the standards developed meet the needs of all users.

The three international organizations that participated in the development of this document share the objective of developing standards for geospatial information:

The ISO Technical Committee 211 Geographic information/Geomatics ( ISO TC/211)
The Open Geospatial Consortium ( OGC)
The International Hydrographic Organization ( IHO).

Additionally, the World Wide Web Consortium ( W3C) and Internet Engineering Task Force ( IETF) are examples of two SDOs that develop foundational standards which are increasingly important in contemporary geospatial applications based upon internet and web technologies. Amongst others, the American Society for Photogrammetry ( ASPRS) and the Geospatial and Remote Sensing Society ( GRSS) of the Institute of Electrical and Electronic Engineers also play roles in geospatial standards development.

These international standards organizations have representative members from government, industry, research, non-government organizations and academia who arrive at decisions through a consensual process. The organizations develop, maintain, and make publicly available open standards that facilitate the ability to publish, discover, access, manage and use geospatial information across a range of applications, systems, and business enterprises.

The Benefits of Joining an SDO

To take advantage of emerging standards and trends, countries and organizations can leverage the global resources of groups such as the UN-GGIM, SDOs, and other major associations mentioned in this document to identify trends and to adopt good practices.

Organizations participate in standards development work of OGC, ISO/TC 211 and IHO to understand implications and assure earliest implementation of standards that will help ease integration of new technologies and data sources. Manyfold benefits can be achieved by formally joining or informally participating in an SDO. These benefits include:

Access to communities of experts to gain and share knowledge.
The ability to influence the development of international standards.
Opportunity to access and contribute to innovative new technologies, with potential funding programs.
Gaining insight into emerging new technology trends and how standards emerge around them.
Trusted advice - regulators can rely on standards as a solid base on which to create public policy.
Forging international partnerships for government and academia.
Building capacity via formal training and development programs.
Contributing to the UN Sustainable Development Goals.

At a minimum, organizations and institutions should consider providing their interoperability requirements to the OGC, ISO, and/or IHO. This does not require much time but ensures that these requirements are documented and considered in the ongoing development of international standards.

The Open Geospatial Consortium (OGC) is an international consortium of geospatial experts from more than 500 businesses, government agencies, research organizations, and universities driven to make geospatial (location) information and services FAIR - Findable, Accessible, Interoperable, and Reusable. OGC’s member-driven consensus process creates https://www.ogc.org/docs/is royalty free. OGC actively analyzes and anticipates emerging https://www.ogc.org/ogctechtrends tech trends, and runs an agile, collaborative Research and Development (R&D) lab - the OGC Innovation Program - that builds, tests and prototypes candidate standards to address community challenges. Membership details and benefits can be found at https://www.ogc.org/ogc/benefits

The ISO is a global network of national standards bodies. Members are the foremost standards organizations in their countries and there is only one member per country. Each member represents ISO in its country. Individuals or companies cannot become ISO members, but there are ways that you can https://www.iso.org/get-involved.html take part in standardization work, either through a national standards body (the member), or by becoming a liaison organization to an ISO committee, in the case of geographic information, this is ISO TC/211. Specific details can be found at https://committee.iso.org/home/tc211

The IHO is the inter-governmental technical and consultative organization that sets global standards for hydrography and nautical charting and provides global coordination and support for the world’s national hydrographic services. It is a recurring recommendation of the General Assembly of the UN and of the International Maritime Organization (IMO), that every coastal State should be a member of the IHO in order to meet its international obligations while maximizing the national economic benefits that accrue from a comprehensive national hydrographic program. More details can be found at https://iho.int/en/become-a-member-state

The W3C is an international community where Member organizations, a full-time staff, and the public work together to develop Web standards. More details can be found at https://www.w3.org/

For further information on how to become a member or participate with these organizations please see their respective websites.

Emerging Standards and Trends

Standards continuously adapt to changes in technologies and other developments. On a regular basis, the UN-GGIM reviews and publishes a five to ten year vision on future trends in geospatial information management. In the most recent version, the top five geospatial industry drivers predicted to have the greatest impact on geospatial information management over the next 5 to 10 years were identified: the rise of new data sources & analytical methods; technological advancements; evolution of user requirements; industry structural shift; and legislative environment. More specifically related to standardization, the Trends provide a forecast of technologies and related geospatial standardization requirements. Amongst others, a mind map of emerging trends, grouping and road map of synergetic trends and a summary chart of Priority Tech Trends are reviewed and published regularly. These documents should be read in the more general context of the importance of geospatial information management to international Sustainable Development Goals (SDGs), as discussed in Monitoring Sustainable Development Contribution of Geospatial Information to the Rio+20 process.

The market is delivering technology advancements on a continual basis. Many of these advancements will help to further improve organizational decision making and reduce cost and effort associated with IT infrastructure. Organizational leadership must be prepared to take advantage of key technology advancements when they become widely available.

Strategy for Standards Implementation

Tiers: A Goal-based Approach to Implementation

Organizations, institutions, and information communities are likely to be starting their standards journey at different points in the capability/maturity continuum, requiring a phased implementation approach that considers the different levels of experience and expertise of the people involved. ^[17] Collaborative initiatives to share and deliver geospatial information are typically oriented around SDI initiatives.

Standards for geospatial information can be seen as a continuum, enabling the achievement of increasing levels of interoperability of geospatial information as more standards are adopted and adapted to keep pace with evolving requirements, technologies, and tools.

Reaping the benefits of standards adoption is a journey and organizations, institutions and information communities are likely to be starting this journey at different points in the capability/maturity continuum. This guide provides a model for the phased implementation of geospatial standards that considers the different levels of experience and expertise of the players involved. Some organizations and institutions are far advanced, others are just beginning, and some are only considering the use of standards. Figure 1.5 describes several "Tiers" that convey a standardization trajectory where the levels of capability and scale of collaboration increase as knowledge and experience are gained.

Standards are a critical element of geospatial information management. In Figure 1.5, the trajectory for increasing levels of capability and collaboration is shown over four Tiers:

Tier 1 - Share maps internally and over the Web.
Tier 2 - Geospatial Information partnerships to share, integrate and use geospatial data from different providers.
Tier 3 - Spatially enabling the nation, large scale (typically national) efforts to develop a comprehensive SDI that provides access to multiple themes of information, applications for using the shared information, and access via a variety of environments (mobile, desktop, etc.).
Tier 4 - Towards spatially enabled IT infrastructure, delivering geospatial information into the Web of data, and bridging between SDI and a broader ecosystem of information technology systems.

Figure 1.5 Increasing levels of capability and scale of collaboration

Decades of experience has shown that lack of consensus, leadership commitment, and a clear governance structure are the key factors limiting the full achievement of the benefits of open standards. Constrained funding, inadequate governance arrangements, a lack of understanding of the value proposition of using a standards-based approach and a lack of knowledge and experience in standards implementation are major limiting factors and are often related to a lack of consensus among stakeholders. With communication between stakeholders comes an exchange of knowledge and experience.

As consensus builds, understanding improves and the willingness of stakeholders to commit resources and coordinate activities in an open fashion grows. This facilitates a continuing, self-sustainable, and self- governed expansion of open standards. Single agency portrayal of basic information develops into collaborative multi-agency standards implementation that takes fuller advantage of emerging technological developments. Recognizing the complexity and constraints, it can be worthwhile to implement standards in an incremental fashion. Full interoperability can take time as an organization or institution matures in both technical and policy terms.

Standards Adoption with Increased Maturity

As the need for interoperability increases, more standards are adopted with increased maturity. Increased capability and scale of collaboration are associated with sets of standards being adopted, as shown in Figure 1.6.

The Tiers represent a series of steps in an organization’s ability to offer increasing levels of geospatial information and associated services as part of an information community. At the beginning of the process (Tier 1), an organization may want to provide access to geospatial information delivered as map images together with a description of them (i.e., metadata).

Figure 1.6 Standards adoption over increased capability and scale of collaboration

As an initiative matures, multiple organizations may wish to collaborate to provide a means to share, search, access, integrate and cooperatively maintain and use a particular geospatial information layer (such as transportation) from multiple sources using web services (Tier 2).

Larger scale initiatives have a goal of establishing a nation-wide coverage of foundation or framework^[18] data as part of their National SDI (NSDI). Foundation data is an accurate set of key geospatial data layers needed most by different users (imagery, elevation, administrative boundaries, transportation, land use, and water features for example). Providing access to this geospatial Foundation Data for a range of application areas is the next level of maturity (Tier 3).

Finally, to address emerging needs and leverage new technologies and opportunities such as crowdsourcing of geospatial information and big data analytics, a community would focus on delivering geospatial information from SDI environments to spatially enable the broader IT infrastructure (Tier 4).

The scale and scope of an initiative in terms of the number of stakeholders and the number of information communities are also presented in this diagram. At each Tier, as more stakeholders adopt standards, the scale of the initiative increases. Likewise, as initiatives move along the continuum from one Tier to the next, from single organization to information communities, the scale of interoperability grows, and the value proposition of standards adoption pays dividends.

The description of the Tiers provided later in this document identifies the specific suites of SDI standards that are used to achieve them, in the form of blocks that are stacked on top of each other. An Inventory of Standards (Appendix 1) provides details on the specific suite of standards associated with each Tier.

Mechanisms for Facilitating Technology and Data Interoperability

Feature catalogues are a common mechanism for enforcing semantic interoperability in geospatial information. Feature catalogues ^[19] describe the semantics of what is meant by 'Tower', so all consumers of the information agree, and what properties of the feature are important to describe it, such as height above ground, height above sea level, construction, or navigational marks (e.g., lights). The feature catalogue contains a record of all the features that are relevant within the organization or jurisdiction. The agreed understanding of what is relevant is known as the universe of discourse.

Ontologies and conceptual models are a means to describe a universe of discourse by describing and categorizing concepts, their properties, and relationships between them. Conceptual models are usually described in the UML and are useful for model-driven development and architectures. They are used to achieve semantic and structural interoperability. Ontologies are a key enabler for the Semantic Web, an extension of the World Wide Web through standards set by the W3C. To enable the encoding of semantics with the data, standards such as Resource Description Framework _(RDF) and Web Ontology Language _(OWL) are used. ^[20] For example, these technologies are used to formally represent metadata in Data Catalog Vocabulary _(DCAT) - a RDF vocabulary designed to facilitate semantic interoperability between data catalogs published on the Web. DCAT enables a publisher to describe datasets and data services in a catalog using a standard model and vocabulary that facilitates the consumption and aggregation of metadata from multiple catalogs.

Data standards are integral to the reuse and repurposing of information to achieve frictionless data supply chains. Having data that is interoperable means that systems and services that create, exchange, and consume data have clear, shared expectations of the contents, contexts and meaning of the data. In addition to promoting standardization for data sharing and reuse, interoperable data supports multidisciplinary knowledge integration, discovery, innovation, and productivity improvements. To be interoperable the data will need to use community-agreed formats, language, and vocabularies (building on the semantic interoperability described above). The metadata will also need to use standards and vocabularies and contain links to related information^[21].

Data integration is needed between and among the various geospatial data themes such as the relationship between a road and a boundary. Integration is also needed between geospatial data themes and geospatially referenced statistical data. Statistics are gathered and summarized according to the topic and point or area of interest. In a geospatial context, point locations and/or boundaries of these additional thematic areas are required to analyze and map the results.

The following are examples of data standards:

The IHO S-100 standard, and its predecessor, _IHO S-57, provides an ISO conformant, tightly defined set of types, features, attributes and relationships alongside a geospatial registry, including formats for data exchange, such that data from different hydrographic offices and equipment manufacturers are fully interoperable.
Coverage data and service standards unify spatio-temporal raster data handling into a common foundation, known as datacubes. Examples include 1-D sensor time series, 2-D satellite imagery, 3-D x/y/t image timeseries and x/y/z geophysical data, as well as 4-D x/y/z/t atmospheric data. Coverage fundamentals are laid down in _ISO 19123-1 / OGC Abstract Topic 6, interoperable data structures are defined in _ISO 19123-2 (also available as _OGC Coverage Implementation Schema), and tailored, modular service ecosystem is provided with _OGC Web Coverage Service (WCS) and _Web Coverage Processing (WCPS) datacube analytics language. These standards are implemented by major open-source and proprietary tools and proven on multi-petabytes, for example, in the EarthServer Datacube federation.
OGC Geoscience Markup Language (GeoSciML) enables national geological surveys to map their national geological models to a global standard, and the _Geodesy Markup Language (GeodesyML), standardizes the encoding and communication of measurements and metadata required for national geodesy.

Application Programming Interfaces (API) are technology standardsthat specify how software components interact with each other through standard interfaces that enable different systems and services to work together seamlessly, saving time, effort, and cost. APIs are one way to reduce the dependency on implementation specifics and make code more reusable. Web services are another way to specify the interaction between computers. Using technology standards gives programmers the ability to later change the behavior of the system by simply swapping the component used with another. This, in turn, provides the flexibility to rapidly mobilize newer technologies and data sources in the future.

The word 'protocol' may mean different things to legal, scientific and computer science audiences. The word can be interpreted in many ways, but the intent is the same: to bring different parties together with a common understanding of a code of conduct in a given situation.

Examples of technology standards are:

The WWW HTTP protocol is the communication protocol that facilitates the communication of web content between machines connected to the internet, enabling users using different devices (PC, mobile phone, tablet, etc.), and different browsers (Internet Explorer, Google Chrome, Firefox) to communicate seamlessly with web servers around the globe.
OGC API – Features (also ISO 19168-1) allows Geographic Information System (GIS) clients to query geospatial information held within servers and databases in a standard way and builds upon standardized Web protocols so the client and the server can be at any locations on the internet.
OGC WCS is a modular framework for spatio-temporal data extraction, including the _OGC Web Coverage Processing Service (WCPS) for search, extraction, filtering, analytics, fusion, and visualization of massive datacubes.

Achieving these increasing levels of interoperability is driven by a desire to provide decision makers with access to a knowledge environment in which geospatial information is accessed and processed across the Web and in mobile environments. Thus, data about people, places and things are linked together to provide a deeper understanding of a given situation (such as a disaster, social, environmental, or economic phenomena).

2. Understanding [Organizational Standards] Needs

The purpose of this section is enabling the reader to:
* Understand which standards are available to assess and address an organization’s needs based on geospatial maturity level or tier.
* Understand how standards are evolving along with changing needs and technologies.

User Needs Perspectives

Understanding the standards landscape to support organizational standards needs is complex and commonly requires expert knowledge and advice. To understand organizational standards needs, it is helpful to look at user requirements from three different perspectives: the user, the data and from the organizational perspective.

The User Perspective

A user must have the ability to easily discover new knowledge, information, or data to address their needs. For example, a researcher may have knowledge gaps and would be required to define the data or information needed to address the knowledge gap. The researcher may check for existing data, define the data/information gap, discover or collect the missing data. A navigator on the bridge of a ship needs to know the depth of the sea as part of planning and conduct of their voyage. He or she is aware of and can discover the depth (bathymetric) information regularly collected and made available digitally via standardized Electronic Navigational Charts published by Hydrographic Offices. A non-expert could also be interested in the planning of offshore wind farms and needs to find the relevant data - How can a non-expert know where to find and discover this data? Similarly, a web developer building a website or application may be unfamiliar with the domain-specific content data and would need to find relevant standards and information.

The Data Perspective

Data providers and users should be aware that there are many considerations around data needs, e.g.:

Ability to access and use data from:
- Legal and security perspectives (e.g. licensing, rights, restrictions, and responsibilities).
- Data format perspective (e.g., requirements for specific software)
- Data volume perspective (e.g., Big Data (imagery, geophysics) vs small data (e.g., laboratory analysis, manual field observations)).
Maintaining and releasing data might satisfy specific or multiple needs depending on data types and collection methods, including:
- Earth and space imaging
- Historic and real-time observations from sensors / Internet of Things (IoT) devices
- Geospatial data themes (e.g., road networks, offshore bathymetry, building footprints)
- Map and Chart Products
- 3D models and simulations

To address these needs organizations should consider adopting metadata, data, and technical standards relevant to their specific domain(s).

The Organizational or Institutional Perspective

Needs can be expressed at different scales: from single to multiple organizations and information communities, for example local to national to global. At the organizational level, there is often a process in place to capture needs and gaps. Gaps and new needs can become part of an organization’s future information policy and annual information plan to be integrated into existing practice. At the regional and global level, regional commissions and international bodies can be established to get a clear overview of national responsibilities / priorities in both data collection and understanding the gaps in data observation and measurements.

This section provides guidance on how to understand the organizational and broader SDI standards needs and gaps, and how standards can address these potential needs and gaps. There are five recommended steps and associated tools that guide users to identify gaps in standards implementation or adoption, as well as determine their needs and priorities. These steps are applicable for all SDI regardless of which level of maturity or tier it is in. More details on suggested standards can be found in the Taking Action Section.

Table 2.1 Five recommended steps and associated tools for understanding and addressing standards needs.
Step	Tool
1. Determine the standards baseline and needs	Framework for managing geospatial data lifecycle (Figure 2.1) Standards Baseline Survey (IGIF SP6, Appendix 6.2) Example of a metadata survey (Appendix 2) to determine adoption of a metadata standard and issues with and priorities of its implementation
2. Choose the tier that matches the needs	The Tier Maturity Matrix (Figures 1.5 and 1.6) Needs Assessment and Gap Analysis Template (IGIF SP6, Appendix 6.3)
3. Match standards to needs.	Standards Inventory (Appendix 1) provides recommended geospatial standards for each Tier. Vocabulary registry (Appendix 3) provides a list of registers publishing generic and domain specific code lists and ontologies
4. Develop a roadmap to address the identified needs	Needs Assessment and Gap Analysis Template (IGIF SP6, Appendix 6.3) Template for a Roadmap (Appendix 4)
5. Identify the additional standards required (i.e., gaps and next actions)	Needs Assessment and Gap Analysis Template (IGIF SP6, Appendix 6.3)

There is no intention to suggest that every standard listed in this chapter and in the Standards Inventory (Appendix 1) must be used at each Tier. Instead, these are meant as recommendations. The standards recommended in this Guide include the three general types of geospatial standards: (1) domain-specific standards, (2) general-purpose standards for geospatial information and technology specifically, and (3) general-purpose standards for information technologies and the internet generally, and also the three types of geospatial standards: (1) information (or content) standards, (2) service or interface standards and (3) procedural standards.

General-purpose: IT, Internet, and Information standards on which geospatial standards may be dependent. While not all of these standards may be required for implementation, they may be required within an implementing community’s operational environment. No information technology standards exist in isolation. There is a rich standards stack that supports all internet, web, and/or mobile applications. Recommended general IT and internet standards ( Appendix 1) are meant as a reference and are by no means all-inclusive. For example, there are many possible IETF, W3C, and OASIS standards for authentication, authorization, and security that could be used when implementing an SDI. The choice of which security standards to use should be determined as part of the system requirements analysis.
General-purpose: Geospatial information and technology standards include good practice standards regarding geospatial data definitions, representation, data quality, general architecture and other aspects of geospatial information and technology. They collectively provide guidance on geospatial data collection, production, and maintenance. Geographic Information standards provide important background and guidance on key concepts of geospatial information definition, organization, and architectural representation. For example, ISO 6709 and 6709/Cor1 describe standardized representation of geographic point location by coordinates, _ISO 19111 defines the requirements for defining coordinate reference systems, and _ISO19161-1 describes the secondary realizations of the International Terrestrial Reference System (ITRS). OGC GeoPackage provides an open, standards-based, platform-independent, portable self-describing, compact format for transferring geospatial information, and the _IHO S-4 provides regulations for International Charts and Chart Specifications of the IHO.

Managing the Geospatial Data Lifecycle

Defining a framework and standards for effective management of geospatial data lifecycle is the first and probably most important step for any organization (Table 2.1) since data supports all levels of capability and collaboration described in the 'Tiers: A Goal-based Approach to Implementation' subsection (Figure 1.5). Organizational success depends on how effectively and efficiently data can be applied in delivering products and services. Potential needs in managing data life cycle could include:

Implementing consistent practices for geospatial data acquisition, management, and archiving.
Discovering geospatial data within organizations.
Defining processes for geospatial data archiving.
Supporting digital geospatial data preservation.

Developed in 2016, the ' FAIR Guiding Principles for data management and stewardship ' can be used to help with development of these capabilities. These guidelines intend to improve the Findability, Accessibility, Interoperability, and Reuse of digital assets, and emphasize machine-actionability (the capacity of computational systems to find and interrogate data with none or minimal human intervention) to support humans in dealing with increased volume, complexity, and creation speed of data. The FAIR Principles provide a very comprehensive framework for applying standards and dealing with all aspects of the data lifecycle, including the ability to collect, organize, describe, and manage geospatial information.

Standardized application schemas and feature catalogs support these capabilities. Quite often, an organization has existing digital geographic information they wish to visualize and share over the web. In this case, the organization would use the referenced standards for maturing their geospatial content collection, management, and update capabilities. These standards should be viewed in the context of the maturity of the SDI and transitioning to Spatial Knowledge Infrastructure (SKI) (Fig 2.2) activities in the organization. For example, a set of standards for transitioning from building portals for data accessed by humans to enable data being machine accessible and actionable via IoT.

Along with data management, organizations need to determine a policy on sharing data, specifically which themes or categories of geospatial information are to be shared. The IGIF SP2 Appendix 2.6 provides an example of aGap Analysis Matrix. Depending on the maturity of the system, sharing could be "view only" (solves the majority of use cases) or actual publication and transmission of physical data. At this level, one or more organizations agree to collaborate and share specific data holdings. Standards at this step in the process are sharing and access agreements, authentication/authorization rules, policies that can be documented and communicated, and/or cartographic symbolization rules.

Organizations should consider using the standards summarized in Figure 2.1 to enable effective management of data and ability to easily apply it for any (re-)use. For details on these standards and the standards associated with the discussion of Tiers below, please see Appendix 1.

Figure 2.1 Geospatial data life cycle and examples of applicable standards (Amended from Source: Geospatial Frameworks)

Functions and Needs by Tier

With reference to the tier diagram introduced in Direction Setting (Figures 1.5 and 1.6) and steps 2-3 of the 5 recommended steps (Table 2.1), the following subsections underscore the geospatial functional and standards needs which organizations could address depending on its tier and system maturity.

Tier 1 - Share Maps Internally and Over the Web

Within a portal context, the most basic requirement is to be able to easily and effectively access and display geospatial information that may be stored in one or more databases and may use different vendor solutions and storage formats. Hence, the functions of visualization and portrayal, and subsequently catalogue and discovery are important at this tier. As identified in IGIF SP6 Appendix 6.3, potential needs at this tier could include:

Visual overlay geospatial information as maps from different sources.
Visualization of digital geospatial information as maps over the Web.
Clear description of geospatial information (metadata).
Discovery of geospatial information via online catalogs.
Interoperability of internal and disconnected operations.

Therefore, the standards most widely implemented for Tier 1 are: OGC Web Map Service (WMS), _OGC Web Map Tile Service (WMTS), _OGC Keyhole Markup Language (KML), and OGC Geography Markup Language (GML) (also ISO 19136).

Associated with visualizing geospatial information may be the requirement to portray the information using an organization’s symbology or cartographic presentation rules. There are available OGC standards to enable the ability to code, communicate and share visualization rules , such as OGC Styled Layer Descriptor (SLD), _OGC Symbology Encoding, and _OGC Web Services Context (OWC). It is important to be aware that OGC web services while still broadly used worldwide are currently undertaking significant reform. The new OGC roadmap ^[22] focuses on the development of a family of _OGC APIs which will 'make it easy for anyone to provide geospatial data to the web'. These standards, built upon the legacy of the _OGC Web Service standards (WMS, WFS, etc.), define APIs to take advantage of modern web development practices.

Most organizations further enhance their capability to support geospatial information and service discovery as well as metadata creation and browsing functionality. Properly populated, standards-based metadata allows end-users. to determine if a specific set of information is "fit for purpose" for a particular use case. The key standard for metadata of geospatial resources which has been widely applied and adopted at regional and national levels is the ISO 19115-X series.

The ISO and OGC standards for catalogue and discovery are widely implemented in national, regional, and local SDIs. Most geospatial technology vendors, as well as open source solutions, support these standards. These standards should be implemented if the community requires the need to search metadata holdings for the geospatial information they require. The metadata catalogue or registry can be made available to services, including clients, using one of the OGC Catalogue Service-Web (CSW) profiles and/or the W3C DCAT data catalog vocabularies.

Tier 2 - Geospatial Information Partnerships

Once the desired geospatial information can be discovered and viewed as a seamless set of maps, then the infrastructure is mature enough to consider publishing content and transmitting data (content) to end users. In this Tier, the community and infrastructure have matured to the point that the services are stable and the community and partnerships are growing, requesting more functionality and capability. Potential organizational or SDI needs identified in IGIF SP6 Appendix 6.3 include:

Ability to share detailed geospatial information within and with other organizations.
Enhanced ability to apply geospatial data for improved situational awareness, analysis, and decision support.
Ability to maintain and improve quality of common geospatial information between cooperating organizations.
Organization agreements to share data using agreed upon standards-based data models.

For example, as more partners (public and private) wish to be part of a CoP to support collaborative sharing and maintenance of geospatial information content, the infrastructure of participating organizations will need to accommodate the use of additional international technology standards and community information model standards. At this stage, organizations would have to consider two of the three key types of geospatial standards:

Information (or content) standards, and
Technology (interface, API) standards.

An information model in software engineering is a representation of concepts and the relationships, constraints, rules, and operations to specify data semantics for a chosen domain of discourse, such as transportation, hydrology, or aviation. The goal of such models is to allow multiple stakeholders across many jurisdictions to have an agreement on how to express data for a specific domain, such as weather, geology, or land use. Such agreements significantly enhance interoperability and the ability to share geospatial information at any time and as required. For some time OGC Geography Markup Language / _ISO 19136 _(GML) Application Schemas and encoding has been the primary OGC/ISO standards-based approach used for modelling, encoding, and transporting geospatial information.

For geospatial information query and access, there are standards which allow the application and user to specify geographic and attribute queries and request that the geospatial information be returned as an encoding. Recommended standards to support this capability can be found in the Standards Inventory ( Appendix 1) and elaborated in the Taking Actions section later in this Guide.

Common distribution formats are GML, _ISO 8211 (used by _IHO S-57 and IHO S-100), OGC _GeoTiff. International open standards are better than proprietary or locally defined formats as they reduce costs and enhance collaboration with outside groups. There are also standard ways for requesting geospatial information, packaging that information, and transmitting the information. For example, if the user wants the transportation theme as a GML dataset or a chart in IHO _S-101 or S-57, then the server-based software needs to be able to generate the information in the requested formats. These requests for publication are performed using simple web calls. Distribution can be in any number of standard formats, such as GeoTIFF or GML files. The required data can be streamed from the server to the client application or for very large files can be uploaded to an ftp site or accessed through flexible web file sharing services (e.g., API) at any time.

Domain-Specific Data Models

At Tier 2, organizations should consider abstract standards or models that describe such geographic information elements as geometry (points, lines, polygons), coordinate reference systems, data quality, time, and so forth. Similarly, domain data modelling extends information modelling by enabling the reuse of concepts, semantics, and information organization (schemas) between related systems. While information modelling typically refers to modelling just one system, domain modelling involves the practice of creating definitions of concepts which are reused between multiple systems. In the standards context this is further extended to imply interoperability of models and platform independence.

Both information models and domain models are relevant to Tier 2 and Tier 3 in the evolution of an SDI. Using such domain-specific, information or content standards helps to guarantee that geospatial information can be encoded and shared with consistent semantics, geometry, quality, and provenance. Further, data models tend to be encoding tools agnostic, meaning the content can be encoded using XML, JSON, and other encoding technologies. Examples of these models include OGC CityGML 2.0, _ISO 19152 LADM, _OGC LandInfra/InfraGML, _IHO S-100 General Feature Model and Geospatial Registry _and IHO S-57 Transfer Standards for Digital Hydrographic Data.

To summarize, domain-specific standards and content data models refer to community agreements on the elements, relationships between elements, semantics and so forth for a specific data set in a given domain. The models are implementation independent and vendor neutral. In order to automate and make the exchange of domain specific geospatial data seamless, consensus needs to be built among the community participants on:

A shared data model for data exchange, in terms of a common understanding and agreement for how different systems "understand" each other.
Common definitions of the different data entities and their properties.
Common controlled vocabularies and taxonomies.

In the case of a transportation network, common agreements and vocabularies mean that:

All stakeholders agree on how to display (symbolize) the transportation network.
All stakeholders agree to what each attribute, such as road width, means in terms of the shared view of the transportation network.
All stakeholders agree to a common view of the road classification system.

This use of common data models is part of the natural evolution and progression of an SDI that leads to the concept of foundation or framework SDI data themes. This evolution is described in greater detail in the Tier 3 discussion. Good references on the domain modelling and content models are ISO 19109 and the https://portal.ogc.org/files/11-107 _OGC OWS-8 Domain Modelling Cookbook. These documents describe rules and good practices for building and maintaining inter-related domain models, which have dependencies on multiple systems. They describe how to build interoperable, maintainable domain models, the challenges and pitfalls faced in building these models, the techniques and patterns that should be applied, and specific tools that can be used.

These agreements enable specific organizations to avoid changing their software or processes by agreeing on a shared data model and semantics (vocabulary, terms and definitions, etc.) used in the model. There are currently many such models available that have been developed and agreed to by international organizations or communities. These models should be considered first prior to considering the development of new data models.

Tier 3 - Spatially Enabling the Nation

In this Tier, the infrastructure is mature enough to: (1) provide access to multiple themes of information via a variety of environments (e.g., mobile, desktop); (2) support deployment of more applications to enhance value, provide increased citizen benefit, increase collaboration between organizations; and (3) integration of an increasing number of geospatial information resources, including volunteer, crowdsourced and real time sensor feeds. Completion of the needs assessment and gap analysis template described in IGIF SP6 Appendix 6.3 would have identified potential needs including:

Delivery of "foundation" or "framework" geospatial information.
Provision of geoprocessing services to perform spatial analysis and modeling.
Development of mobile applications.
Integration of real-time sensor feeds.
Customized products and applications.

Standards are available to facilitate implementation of geoprocessing and analytics services, grid systems, mobile applications: capturing and integrating real-time sensor data, and geosemantics. These trends are further elaborated in the 'Taking Action' chapter and relevant standards or frameworks can be found in Appendix 1.

Geoprocessing & Analytics– OGC Web Processing Service (WPS)and _OGC Web Coverage Processing Service (WCPS)
Grid Systems – OGC Discrete Global Grid Systemsand _http://www.iso.org/standard/32588.html[ISO] 19170-1
Mobile Applications – OGC Open GeoSMS and _OGC GeoPackage
Real-Time Sensors – OGC Sensor Web Enablement (SWE) standards and _OGC SensorThings API
GeoSemantics - The Spatial Data on the Web Interest Group (W3C/OGC) is one of the communities that provides significant input to development of good practices and vocabularies that encourage better sharing of spatial data on the Web; and identify areas where standards should be developed jointly by both W3C, OGC and ISO, including _OGC GeoSPARQL, _OGC API Features/ _ISO 19168-1 and _ISO 19150-1/ _19150-2/ _19150-4.

An excellent example of operational use of OGC SWE standards is the Debris Flow Monitoring System deployed in Chinese Taipei. This program uses OGC Web Services and OGC SensorThings standards integrated into a monitoring, modelling, and alerting infrastructure. (See also: https://youtu.be/6Hb2iXQQ8TY).

*Tier 4 - Towards Spatially Enabled IT Infrastructure

Tier 4 involves the transition of current SDI into a broader Spatial Knowledge Infrastructure (SKI) that can be strategically planned based on: (1) emerging standards and technology trends that are addressing known gaps, challenges and needs (refer to Direction Setting chapter - Emerging Standards and Trends); (2) delivering geospatial information into the Web of data and bridging the SDI to a broader ecosystem of

information systems (Figure 2.2), and (3) The SDI to SKI -Maturity Matrix (Figure 2.3). A