Standards for Geographic Information and Services Status and Overview of Relevant Standards and their Implementation Douglas Nebert, GSDI/FGDC

Why Geo Standards? Standardization lets peers communicate Minimizes cost of uptake of new information Maximizes utility and stability of information products Permits more applications to operate under known conditions

Roles of Consensus Organizations ISO provides general purpose standards and specifications as guidance to implementation Industry Consortia provide technical implementation specifications National/Community groups define common practices, content, and interaction within and outside the group

Introduction to Standardization Organizations Many standardization activities exist with different roles and responsibilities that are relevant to implementing SDIs: International Organisation of Standardization (ISO TC 211, TC 204, JTC-1) World Wide Web Consortium (W3C) OpenGIS Consortium (OGC) National Standards Organizations

Geospatial Standardization OpenGIS Consortium, W3C Software interfaces (Implementation Specifications) GSDI Regional SDI Coordination Endorsed practices and specifications SDI Other NSDIs ISO TC 211 Foundations for implementation. (Abstract standards) National Standards Content standards, Authority for data

Interactions ISO TC 211 TC 204 JTC-1 National Standards Organizations Class A liaison XML Protocol (XMLP), XML Signature, I18N Class C Liaison: XML, I18N OpenGIS Consortium (OGC) Internet Engineering Task Force (IETF) ISO W3C: HTTP, PNG, RDF, SOAP/XMLP (Web Services Activity), XML, Xlink, Xpath, Xpointer, XSL/XSLT, XML Schema OGC: Web Map Server, Web Feature Server, GML, Web Coverage Server, Style Layer Descriptor, Catalog Service ISO: Ref Model, Terminology, Conformance testing, Profiles, Spatial Schema, Temporal Schema, Feature Cataloguing Methodology, Spatial Ref by Coords and Ids, Quality, Metadata, WMS, GML, LBS, Registration of Geo-information Items Metadata Profile, Data Content Standards, etc. TC 211 TC 204 World Wide Web Consortium (W3C) JTC-1 Provide expertise & candidate stds. Review & approve stds. Facilitation Bodies Establish definition of and terms of engagement in *SDI GSDI ANZLIC PCGIAP FGDC PC-IDEA INSPIRE GeoConnections CODI/UNECA AGI … I18N is W3C Internationalization Activity National Standards Organizations Adopter/ Implementer Community

Community Coordination Regional and State coordination groups provide a forum for selection and information on building a consistent network of solution National coordination bodies provide a forum for agreement on the common adoption of a suite of standards and practices that as a whole will function as a Spatial Data Infrastructure The Global Spatial Data Infrastructure (GSDI) initiative seeks to promote compatible SDIs worldwide

ISO Technical Committee 211... ... has the objective to develop a family of international standards that will: support the understanding and usage of geographic information increase the availability, access, integration, and sharing of geographic information, enable inter-operability of geospatially enabled computer systems contribute to a unified approach to addressing global ecological and humanitarian problems ease the establishment of geospatial infrastructures on local, regional and global level contribute to sustainable development

TC-211 Primary Member List Australia Austria Belgium Canada China Czech Rep. Denmark Finland Germany Hungary Italy Japan Republic of Korea Malaysia Morocco New Zealand Norway Portugal Russian Federation Saudi Arabia South Africa Spain Sweden Switzerland Thailand Turkey United Kingdom United States of America Yugoslavia 3

ISO TC211 Work Items

Relevant ISO TC 211 standards 19109 Rules for Application Schema 19110 Methodology for Feature Cataloguing 19115 Metadata (Data) 19119 Services (Metadata) 19128 Web Map Services (WMS) 19138 Geography Markup Language (GML)

Problem: The ability to exchange software and data models between software development (CASE) systems and data in a system-and vendor-neutral manner Solution: Unified Modeling Language (UML) Evidence: Support by software design and CASE environment, ISO TC 211 endorsed conceptual schema language

What is UML? Unified Modeling Language UML is an industry standard language for visualizing, specifying, constructing, and documenting artifacts of a software-intensive system Platform-neutral environment for abstract modeling of data and processes Adopted as the Conceptual Schema Language for ISO TC 211 Core message -- second bullet UML can be used to communicate system and software design throughout the life cycle 9

UML Concepts A community standard led by the Object Management Group (OMG) The UML may be used to: Model a system & its major functions using use cases and actors Illustrate use case realizations with interaction diagrams Represent a static structure of a system using class diagrams Model the behavior of objects with state transition diagrams The last set of slides briefly introduces most of the UML notations. NOTE: Not all notations are covered due to time constraints 12

UML Diagrams Use Case Diagrams Scenario Collaboration State Component Deployment Object Statechart Sequence Class Activity Models

UML Class Diagram

World Wide Web Consortium Mission: “to lead the World Wide Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability.” A Recommendation is work that represents consensus within W3C and has the Director's stamp of approval. W3C considers that the ideas or technology specified by a Recommendation are appropriate for widespread deployment and promote W3C's mission. Such specifications developed within W3C must be formally approved by the Membership. Consensus is reached after a specification has proceeded through the review stages of Working Draft, Proposed Recommendation, and Recommendation.

W3C Contributions HTML HTTP PNG SOAP/XMLP SVG URI/URL XHTML XLink XML XML Query XML Schema XPath XPointer XSL and XSLT CSS DOM Hypertext Markup Language HyperText Transport Protocol Portable Network Graphics Simple Object Access Protocol XML Protocol Scalable Vector Graphics Uniform Resource Identifier/Uniform Resource Locator XHTML Xlink eXtensible Markup Language Xpath: system to navigate through XML documents and perform operations Xpointer: allows elements to be inserted into XML documents in order to create and describe links between resources XSL: XML Style Language XSLT: XML Style Language Transformation CSS: Cascading style sheets DOM: Document Object Model

Problem: The inability to express a common format and support it with widely available software parsing tools Solution: XML and XML-Schema provide the context and structure to support encoding of many types of information. XSLT permits the easy transformation of XML Evidence: Implemented by hundreds of software products and solutions providers

XML 1.0 eXtensible Markup Language is a partial subset of Standard Generalized Markup Language (SGML: ISO 8879:1988) Intended to store the structure and relationship of information in a readily parseable format Expressed as characters, though element contents can also be numbers or links Non-Latin character sets are also supported in XML

What is XML Schema ? Another more powerful data description language to assist in validation of XML It is more precise than (and replaces) a DTD. It is the workhorse of XML! Supports data types and restrictions Simple and complex structures © Galdos Systems Inc. April 2002

SOAP – Simple Object Access Protocol “I can deliver your message over HTTP, HTTP/S or SMTP “ Your message SOAP provides an XML envelope for your message

What is SOAP ? A messaging protocol: an XML syntax for sending messages over the Internet via HTTP, SMTP, etc. W3C work item to move SOAP to the XML Protocol (XMLP) Fundamental part of message handling via Microsoft .NET © Galdos Systems Inc. April 2002

SOAP Design SOAP Message <soap:envelope> HTTP Headers <soap:header> </soap:header> <soap:body> XML DATA GOES HERE </soap:body> </soap:envelope> HTTP Headers SOAP Envelope SOAP Header SOAP Body

Why SOAP ? Simple, extensible, platform-independent (cf. COM or CORBA) Works across firewalls since it is transported over HTTP and HTTP/S. Widely supported in commercial tools. Many language bindings are available: Java, C++, Python, Perl, etc.

Vendor-specific Web Services Built on SOAP or .net architectures Microsoft Terraserver.net and MapPoint .NET solutions for web map interaction ESRI ArcWeb SOAP-enabled map interaction and display Anyone can implement Web Services, but unless the vocabulary and messages are well-known, interoperability is hindered

OpenGIS Consortium OGC Vision A world in which everyone benefits from geographic information and services made available across any network, application, or platform. OGC Mission Our core mission is to deliver spatial interface specifications that are openly available for global use. Focus on interoperability of software at the interface level to promote plug-and- play components for geographic information interchange Not-for-profit, international consortium 220+ industry, government, NGO and university members

OGC Specifications Simple Features Access (SQL, CORBA, OLE) Catalog Services Grid Coverages Coordinate Transformation Services Web Map Server Interfaces Geography Markup Language Web Feature Service Filter Encoding Specification Styled Layer Descriptor Web Coverage Service

Problem: To make a request for a map from different map services regardless of vendor using the same request language Solution: OGC Web Map Server interface Evidence: Broad commercial implementation as an add-on to proprietary map services

OGC Web Map Server 1.1.1 Establishes a common vocabulary for the request and delivery of a raster graphic based on a number of parameters using GET/POST Three operations: Capabilities: returns service and layer information Map: returns map based on request arguments FeatureInfo: returns attribute information for the selected feature(s) Now supports SLD reference to apply custom style to layer

Client Web Browser getMap Software A Data Software B Data Request Response with single or Multiple maps as GIF/JPEG Integrative Web Server getMap WMS Interface Software A Data Software B Data

GetMap Request Example: http://b-maps.com/map.cgi ?WMTVER= 1.0.0 &REQUEST=map& SRS=EPSG%3A4326&BBOX=-97.105,24.913,78.794,36.358& WIDTH=560&HEIGHT=350&LAYERS=BUILTUPA_1M%3ACubeWerx, COASTL_1M%3ACubeWerx,POLBNDL_1M%3ACubeWerx &STYLES=0XFF8080,0X101040,BLACK&FORMAT=PNG&BGCOLOR=0xFFFF FF& TRANSPARENT=FALSE&EXCEPTIONS=INIMAGE&QUALITY=MEDIUM

Problem: No vendor-independent way to format vector feature and attribute information for exchange over the Web Solution: Geography Markup Language (GML) Evidence: Commercial implementations and national service implementations (Ordnance Survey, UK)

Geography Markup Language (GML 2.1.2) OGC “Adopted Specification” (GML 2.1.2 currrent) for encoding spatial information. A set of XML technologies (schema fragments) for expressing spatial data on the Internet. Emerging international standard for spatial data—endorsed by 200 + companies and agencies around the world. Propose GML Version 3.0 by early 2003 © Galdos Systems Inc. April 2002

GML: What is it? OGC Web Feature Service getFeature() Geographic Data Server GML/XML Data Links to other geographic data

Feature : named list of properties FeatureType (road) name description geometry length direction

GML Feature GML Namespace <exp:Building fid = “st100”> <exp:noFloors>100</exp:noFloors> <exp:use>Residential</exp:use> <exp: surfaceArea>100000</exp:surfaceArea> <exp: frontsOn>Georgia Street</exp:frontsOn> <exp:streetNumber>1150</exp:streetNumber> <gml:locationOf> <gml:Point srsName = “ … “> <gml:coordinates>55661.1454, 454656.67</gml:coordinates> </gml:Point> </gml:locationOf> </ exp: Building> GML Namespace © Galdos Systems Inc. April 2002

Problem: No consistent way to request and receive well-known packages of vector information as a Web service Solution: OGC Web Feature Server provides for request and response of vector data Evidence: OGC WFS recently approved but beta implementations available from main GIS vendors

OGC Web Feature Server 1.0 Provides discovery and request interfaces for selecting “vector” spatial data and their attributes May use OGC Filter Expression or other query language Returns “raw” data structures as ASCII, XML, GML May support transactional locking

OGC Web Feature Server WFS OGC Web Feature Server Specifications V 1.0.0) REQUEST: GetCapabilities DescribeFeatureType Query Transaction (insert, modify, delete) Lock Feature Schema Synchronization App. Server Presentation/ Analysis Client OPERATIONS: Describe Capabilities Describe Feature Schema Get a Feature Insert a Feature Update a Feature Delete a Feature Modify Feature Schema Lock Features RETURN : Capabilities (XML) Feature Schema (XML/S) Feature + Attribute (XML- GML) Feature Transaction (XML- GML) WFS WFS Feature access /modification

Chaining/Stacking OGC Services Client Web Browser Application Application WMS interface Rendering Map server Map Server service WFS interface Feature Delivery Feature Server Feature Server service SFA interface Feature Access Native DBMS Simple Feature Access Server

Scope of National Solutions Content Standards for Fundamental Data Feature Type Catalogs Standard Data Models for Exchange Unique Identifiers on Features Place names (Digital Gazetteer) Geodetic Reference Systems National Information Profiles of International Standards (ISO) Data Policies and Laws

Calls for requirements Conceptual process diagram of Geospatial OneStop Who? To whom? When? How? Call for business requirements of portal Portal Team Review State and E-Gov User Requirements Target 22+ e-gov initiatives and other e-gov Face-to-face Town Hall Discussions Document existing and planned data Service and Data Clearinghouse register Develop consolidated use cases Initial Portal Functional Design Establish interface to services Prototype specific G2G functions Augment portal functionality refine Prepare Questions, Organize Extract data requirements Prototype map/data services Finalize map/data services refine Requirements Team e.g. transportation Under ANSI INCITS L1 Standards Teams Compose/ convene 7 MATs Write draft std docs Extract common data requirements Construct Draft Model Construct Draft Standard Vote at ANSI INCITS L1 Vote at ANSI FGDC Endorsement revise Calls for requirements and participation revise Public Review Public Review time (not to scale)

Standardization approach Convene subject matter experts with modelers in a facilitated environment to develop a content standard for common themes of data Meet under the auspices of the ANSI/INCITS organization to maintain an open and inclusive process

The Framework Core Data Content Standards… Define a well-known package of GIS data in UML with XML representation that can be exchanged without negotiation for immediate use for multiple common uses More robust packages can be defined and exchanged by the same approach, but one must support Core at a minimum Do not define the internal data models used in mission critical systems, only a package for import and export

Framework Standards Base Standard Source – INCITS/L1 Air Elevation Rail Air Roads Elevation Transportation Transit Base Standard Waterways Cadastral Geodetic Control Thematic modules contribute to the Base Standard to establish common content, required elements, for the collection and exchange of NSDI framework themes. The goal is to decrease costs of acquiring and exchanging framework data for creators and users through the common description of the content of these seven critical themes. Governmental Units Orthoimagery Hydrography Source – INCITS/L1

Participation and Requirements Extract features, identifiers, attributes, and relationships required for each Framework theme from requirements analysis conducted through the participatory process Request for participation in process teams: Modeling Advisory Team Contributor Subscriber Reviewer

Generalized Modeling Approach Universe of Discourse (each of 7 communities) Conceptual Model Feature Model in UML expert intervention Application Schema Conceptual Model using ISO 19118/19103 objects in UML UML-XML encoding transform Common Community Data Transfer in XML-Schema (GML) Data Transfer Schema XML validation Encoded Feature Data in XML

Common Elements of Core Feature types (classes) included Unique feature identifier system Basic attributes Controlled vocabulary, codes, authorities Valid at a range of scales and resolutions Multiple representations of same features possible

Interoperability based on a common data model for data exchange Content Model import export Mission System 1 API API Mission System 2 Core Framework Encoding export import API Mission System 3

Navigating many choices Standardization should be a least-cost means of establishing a common means of interaction between participants in a process Community facilitators can play a critical role in building consensus on a requirements-based architecture and then specifying the context of relevant standards, specs, and practices to be adopted

The players NSDI ISO National Standards National Organizations OpenGIS Consortium (OGC) World Wide Web Consortium (W3C) ISO Adopter/ Implementer Community National Standards National Organizations NSDI blueprint Users Policies, Agreements, Technologies Coordination

A blueprint for SDI Metadata for data and services Data content standards (UML models) for exchange of individual data themes Data formats for file archiving, download Data encoding for the Web (XML/GML) OGC Spatial Web Services Specifications: Web Map Services Web Feature Services Draft Gazetteer Profile of WFS (Placename Service) Catalog Services (Clearinghouse)

Activities and Standards in SDI ISO 19115, 19119, 19139 OGC Catalog Services W3C XML OGC GML Metadata Catalog http, Z39.50 Data Production GAZ Web Services WMS Formats http Data User WFS ftp, CD Data Services Formats ISO Feature Catalog SDTS, VPF, … National/Intl Content Standards Internet

Needs and Opportunities Informing potential adopters about relevant standards and their implementation Promoting a logical architecture for the interaction of standards-based systems Building and sharing common feature catalogs, data content, and data exchange standards for files and the Web

Questions? Douglas Nebert FGDC Secretariat ddnebert@fgdc.gov (703) 648-4151