Standards and the US National Spatial Data Infrastructure

1. Standards and the US National Spatial Data Infrastructure Improving access to geospatial information

2. Overview • FGDC and GIS Standards • Division of labor in standardization

3. FGDC Objectives • To promote access to and usage of digital geospatial information of national and local value • To improve discovery of and public access to federal geospatial data resources • To reduce duplication of effort among public sector organizations developing geospatial data

4. FGDC and Standards • FGDC provides a public forum for the development of content-based standards for general or information community use • Examples: • Content standard for digital geospatial metadata • Framework data standards

5. Endorsement of External Standards • In 2010, the FGDC endorsed a set of 64 external geospatial standards as a reference set for community use • Derived from a much longer list of DoD IT Standards Registry (DISR) • Point of collaboration with the Geospatial-Intelligence Standards Working Group (GWG)

7. ISO Standards (TC 211) • FGDC participates in ANSI/ISO standardization under ISO TC-211 • Some areas of participation: • Metadata content standard • Services • Encoding • Data Quality

8. FGDC and OGC • FGDC participates in the Open Geospatial Consortium for the development of common implementation specifications to improve access to spatial information • Users benefit from vendor support of information access specifications and integration of solutions into GIS workflow

9. OGC Specifications • Designing implementation solutions for discovery through Catalog Services • Approved: Simple Features SQL, KML, Web Map Server Specification, Geography Markup Language (GML), Catalog Services Specification, Web Coverage Services, Web Feature Services, Sensor Observation Service • Going beyond Simple Features to raster (coverage) services and eventually distributed GIS

10. GIS Standards Turf • ISO TC-211 is focused on the abstract specifications, design framework and international political consensus (what) • National standards support the development of community content standards (who, why) • OGC specializes in extending the abstract model into implementation specifications (how)

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

12. stores service info UI UI Metadata UI UI managed through managed through are derived for each managed through Metadata DB/Index Data Catalog Service Service Registry/ Catalog Metadata enter/update is exposed to the Internet through a are loaded to or stored in synchronize API queries may reference instances performs lookup to grab operation signatures may be coupled to or integrated with are derived from API is exposed to the Internet through a Catalog Client may send data to GEOdata Access Service feeds server info to Spatial Data Data/File Management System makes maps from stored in distributes to and collates from multiple Web Mapping Service draws layers from API enhances query with API managed through Gazetteer API Gateway UI enhances query with Other Service API Thesaurus provides application access through 1 2 3 Symbols current planned Software/Service 1. builds query screens for 2. submits queries/requests to 3. returns search responses API UI Information SDI Interaction Diagram revised 7-May-2003 ddnebert@fgdc.gov interacts with interacts with API UI Interface Application Client Web Client now: planned.: Function

13. GML 3.0 XML may return deployed as used for transport validates HTTP XML Schema validates against transformable to UML ISO Spatial Schema harmonized with expressed in Standards are monolithic yet interdependent WFS 1.0

14. Framework Themes • Themes providing the core, most commonly used set of base data are known as Framework Data: • Geodetic Control, • Orthoimagery, • Elevation and Bathymetry, • Transportation, • Hydrography, • Cadastral, and • Governmental Units.

15. Additional Data • Geographic names (toponymy) layer • Land cover/vegetation/wetlands • Cultural and Demographic Statistics • Buildings and Facilities • Natural hazards • Soils and Geology • Utility distribution networks

16. Framework Standards • In 2008, the FGDC published eleven Framework standards • Included an abstract model (in UML) and had companion XML schema files

17. Community 6. Forward Draft for Review and Approval 3. Review Application- Neutral Content Model 1. Requirements Encoding (XML) 2. Design Modeling Advisory Team (Team of Experts) Design Process 4. Comments 5. Refine

18. Conceptual Model • A conceptual or logical design of the information that preserves the native groupings of the data • Is implementation- and software-independent to provide a stable base for current and future implementations • Describes graphically and with narrative the design assumptions and conditions • Currently expressed using the Unified Modeling Language (UML)

19. 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

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

21. Class Diagram • Captures the ‘vocabulary’ of a system • Built and refined throughout development • Purpose • Name and model concepts in the system • Specify collaborations • Specify logical database schemas • Developed by analysts, designers, and implementers

22. UML Class Diagram

23. The UML • Useful for diagramming systems, objects, and relationships • Many diagrammatic conventions • Many ways to diagram the same thing • Can serialize the UML as XML (XMI) • CASE tools or transforming programs can create implementation bindings • FGDC is hosting a UML-to-GML transform program for convert UML into XML Schema

24. UML per Rational Rose Implementations Conceptual Models Oracle Table Schema User Interface content Java Program Code Integrated Development Environment UML procedures and structures r u l e s structures XML Schema Document

25. Start Modeling • Review existing models from FGDC and The National Map efforts and adapt/adopt them if possible • Identify theme experts who are either producers or users of digital geographic data • Apply modeling expertise to work with the experts interactively to build model

26. Framework Data Modeling • Based on provider and consumer requirements for GIS and mapping, focus on a specific theme of information • Convened a group of experts with modeling support and have them bring any relevant systems designs or requirements documents • Built models that support a common, not universal, set of needs • Publish model and narrative in a standard

27. Common Modeling Baseline • 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

28. Feature Catalog • One first step toward developing a conceptual model of geographic information is to construct a Feature Catalog • Feature Catalog includes: • Feature types, definitions • Attributes, definitions, data types • Domains, expected values and types

29. Catalog as Abstract Model • Feature Catalog describes what information is included in a given data theme and what properties and values are stored there • A feature catalog is not an implementation model but can, with rules, be used to create one or more implementation models • Implementation guidance supplements abstract or conceptual models

30. Hydrography Permanent Feature ID Feature Type Code Feature Name Feature Qualifier Geometry : Geometry Type Enumeration Permanent Feature ID Source Scale Denominator : Integer GNIS-ID name Example UML Model(example excerpt from the hydro model, prior to face-to-face session in November) Dataset describedBy Metadata is at a Metadata collection level; for Time of sample example it will apply t POC o ISO, FGDC etc. etc. HydroLine HydroArea HydroPoint Reach ID Elevation of area ReachID From position Water surface basis height Periodicity : Periodicity Type Enumeration To Position Area of feature Cartographic feature type code Length Region ID Hydrographic feature code

31. Example Tabular Description

32. Going from the Abstract to Implementation • Conceptual modeling yields the natural organization of the data but not a specific implementation • For interoperability in the exchange of data, an agreement on encoding and format is required • CASE tools and scripts can convert UML designs into specific implementation schemas

33. Application Schema • Name for the rules that define the content, relationships, attributes, domain values and constraints in a specific implementation environment • UML may be converted into XMI to load the model design into a different modeling software • UML may be converted to an XML/GML Schema Document

34. Content + Format validation Conceptual Data Model Implementation model/schema for Format A Format A Data encoding

35. Creating a Standard Data Content and Exchange Standard • A standard facilitates interoperability if it includes both the conceptual data model and one or more implementation annexes with specific guidance for content validation Conceptual Data Model Narrative with context, obligation, examples Implementation Schemas

36. Introduction Scope and Context Data Content Model in UML Descriptive table and narrative Annex: Encoding using XML (GML 3.0) Framework Standard Outline

37. Geospatial Services • Increasingly geospatial data can be accessed in real-time over local area networks and the Internet as if it were local data • Multiple organizations can benefit from the data being staged and maintained once and used many times • Desktop software and portals can use these services over the Web

38. Framework Interoperability Pilot for Transportation • OpenGIS Consortium (OGC) is assisting in modeling process to define proper UML that conforms to ISO rules and can be implemented as GML • Contract with OGC members to implement Web Feature Services to extend multiple available data systems (U.S. and Canada) • Implement a Web client that can display and query multiple Framework data sources based on the common data model • Approach to be followed for other themes

39. Establish WFS on agreed content nationwide WFS Mission System A Web Feature Browser/ Client Application translation utilities GML (XML) Native Format Mission System B WFS P B private schema public schema transformation rules

40. http://www.fgdc.gov Doug Nebert ddnebert@usgs.gov