The Open GIS Consortium, Geospatial Data Sharing, and Interoperability BAAMA April 18, 2002 Phillip C. Dibner Ecosystem Associates

State of the (non-) Union Tens (100s?) of billions of dollars worth of spatial data already archived at diverse sites Too large and expensive to move and convert Prohibitively inconvenient to store and manage centrally Operationally constraining and administratively challenging to mandate a single-technology supplier

The Solution: Interoperate Data remain in place No constraints on maintenance operations or policy Existing in-house tools and applications remain viable Only the interfaces need be well-defined among interoperating clients and servers

Open GIS The Open GIS Consortium (OGC) grew out of the need among federal agencies to share data. Currently a collaboration of more than 230 vendors, integrators, government and private agencies, universities, and end users. Abstract Specification: –Defines basis of discourse for standards under development –17 volumes. –A living document 7(+) publicly available Implementation Specs published. Many more in various stages of creation or refinement. Close relationship with ISO (esp. TC 211) Uses other standards where possible

Organization of OGC Planning Committee –Steering, policy, general management and oversight Technical Committee (TC) –Develops specifications, discussion papers, other technical communications. –Special Interest Groups (SIGs), Working Groups (WGs) that develop specifications, and Revision WGs that revise specs. –Consensus process. Interoperability Program –Practical testbed and pilot projects –Speeds specification development –Helps bring products to the marketplace

A Snapshot of SIGs, WGs, and RWGs Architecture Catalog Features Decision Support GML Metadata Image Exploitation WWW Mapping Location Services Information Communities and Semantics Telecommunications and Utilities Earth Observation Defense and Intel Natural Resources and Environment Disaster Management and Public Safety Europe Australia Technology SIGsDomain SIGs Coordinate Transformation WG & RWG Grid Coverages WG Catalog RWG Open Spatial Publishing and Discovery Infrastructure (OSPDI) WG Simple Features for CORBA RWG WGs and RWGs

Simple Features Specification Profiled for CORBA/IDL, SQL, and OLE/COM Includes a Geometry interface with support for: –Full suite of SRS and coordinate system interfaces: Geodetic and non-geodetic SRS Coordinate units Projection and coordinate transform interfaces –Point, 1-D, and 2-D geometries Points and point strings, lines and line strings, curves, 2D surfaces, rings, polygons, and corresponding collections –Relational operators Typically boolean Equals, contains, touches, within, disjoint, crosses, etc. –Set operators Typically geometry-valued Intersection, union, difference, buffer, convex hull, etc. Sequences of name/value pairs for non-spatial properties Supports Collections and Iterators

Coordinate Transformation Service 3 Packages: Position, Coordinate Systems, Transformations –Enables creation of standard and customized CT objects. –Each CT object includes a source and target Coordinate System. –Also includes an instance of a mathematical transform class, which performs the actual transformation of positions in the source CS to positions in the target CS.

Geography Markup Language (GML) XML implementation of Simple Features and increasingly more comprehensive set of objects. Rapidly becoming - or has become - the lingua franca for the transport and storage of geographic information. Specified in XML Schema Currently undergoing its third revision; Version 2.0 has been released.

Web Mapping Server Exposes its datasets through a standard CGI interface. Supports heterogeneous data formats, both image and vector, at source locations. May allow for querying objects within the data layers it provides Returns a map image - a picture. Formats that support transparency (GIF, PNG) allow images to be stacked.

Web Mapping Servers and Client Whoville Cedar Lake Integrated View Internet Crime Social Services Land Parcel Federal Program Weather Environment Framework (Clearinghouse) Adapted from Web Map Server Demonstration presentation © 2000 OGC

NOAA Hurricane Image of the Gulf of Mexico Source: Web Map Service Implementation Specification OGCProject Document r2

Political, Coastline, and Populated Areas, Southeastern United States Source: Web Map Service Implementation Specification OGCProject Document r2

Combined Hurricane Image and Population Map Source: Web Map Service Implementation Specification OGCProject Document r2

WMS Interface: Overview GetCapabilities (required): Obtain service-level metadata, which is a machine-readable (and human-readable) description of the WMS's information content and acceptable request parameters. GetMap (required): Obtain a map image whose geospatial and dimensional parameters are well-defined. GetFeatureInfo (optional): Ask for information about particular features shown on a map. A WMS or layer that supports this function is called queryable.

Legend Roads Water Buildings Map Layers Web Map Service GetCapabilities Capabilities XML Document with Layer Information GetMap Rendered Map Image WMS Interface: Operation Client

Cascading Map Server Supports the WMS interface to client applications Acts like a client itself, by accessing and collating data from a variety of servers Applies coordinate transforms, reprojections, and image processing as needed Returns the composite image to client applications

Cascading Map Server Web Browser Map Server internet Cascading Map Server Map Server internet Capabilities Integrator Map Integrator JPEG WGS 84 GIF NAD 83 PNG AL St Pln GIF WGS 84 Different viewer client in browser! Adapted from Web Map Server Demonstration presentation © 2000 OGC

Web Feature Server (WFS) Passes vector data (not pictures) between server and client Why? Processing of various sorts, including flexible portrayal Encoding in current implementations is GML Basic WFS: –GetCapabilities –DescribeFeatureType –GetFeature Transactional WFS: –Transaction –LockFeature Not yet a published standard - but maturing rapidly

Web Coverage Server (WCS) Coverage data, not pictures. Like WFS, but for imagery and other coverages. Why? Flexible portrayal, image processing, etc. Supports many formats and encodings. Not as mature as WFS, but under intensive development. Formally, a coverage is a mathematical function: a mapping from a geographic (or temporal?) domain space to some sort of range space, typically a measurement or observation. Metadata are complex. Much active debate about format and content of capabilities document.

Catalogs and Registries Element 13 of the Abstract Specification Stateful Catalog Interface Implementation Specification: (doc ) –Coarse and fine-grained models for tradeoff between detailed control and flexibility –Defines structural as well as dynamic models Stateless version is in specification review process. Communicates with clients via Capabilities Documents Next version is being actively developed and debated –Likely based on ebRIM –Next step towards Web Service Chaining

Sensor Web Components © 2001 OGC, Inc. All rights reserved.

A Sensor Web Client View © 2001 OGC, Inc. All rights reserved.

Other Specs - “In Play” UOM: Units of Measure. Developed with coordinate units in mind, has general applicability. SLD: Styled Layer Descriptors. When combined with a WFS, provides for a stylable WMS. WTS: Web Terrain Server. Renders oblique views that incorporate elevation data. XIMA: XML for Image Markup and Annotation. CPS: Coverage Portrayal Service. Measurements and Observations: relevant to Sensor Web, and to the range space of a WCS.

Constellation of Sensors SCS Client Sensor Collection Service Map Layers Web Map Service Web Feature Service Current OGC Data Retrieval Operations Web Coverage Service Vector Data Coverage Data GetObservation Measurement Collection GetCoverage GetFeature GetMap Feature Data Rendered Map Image Coverage Data WCS Client WFS Client WMS Client Coverage Portrayal Service SLD Service

Current Issues Which new specifications are the wave of the future, which not? When to start adopting? Consistency among different services: consistent schema for capabilities document, both for operation and for discovery. Balancing need to innovate with producing a stable basis for products in the marketplace.

OGC Interoperability Program OGC Interoperability Program OGCSpecificationProgram Interoperability Initiative Testbeds Pilots Insertions FeasibilityStudies Infrastructure Initiatives WMSs WFSsWCSs CMS External (3 rd Party ) Repository Services Repository Services Operators User Interaction Internet OGC Network™ PlanningStudies Development Initiatives © 2001 OGC, Inc. All rights reserved.

Working Groups Working Groups Working Groups Role of Initiatives and Working Groups Working Groups DIPRv1 Working Groups DIPRv2 Working Groups IPR TC DP/Other Requirement Viability Consensus IP Work Items Development and Testing Cycles OGCNetwork © 2001 OGC, Inc. All rights reserved.

Practica - On the Ground with the Interoperability Program* * WMT-1 and -2 –Genesis of the Web Map Server –Revealed need and opportunity for GML Upper Susquehanna- Lackawanna Geospatial Fusion Testbed –GeoParser, GeoCoder, Gazetteer –Location Organizer Folder (LOF) spec, for an analyst to keep track of the datasets collected for a given project CTI MPP-1: Military Pilot Program, Phase 1 OWS: Web Services Initiative (3 threads): –1.1: Complete –1.2: Kicks off May 20 OpenLS: Location Services CIPI: Critical Infrastructures ODMS MMI: Multihazard Mapping GISD: Sustainable Development Etc. * Complete * Ongoing or not yet started

Example from Civil Technology Insertion USACE MVD project sites (yellow) from ArcIMS/WMS Oil facilities (green) and high tide line (off-white) from LSU Geomedia/WMS, over Compusult basemap.

Cross-Agency Data Sharing Enhanced Landsat data from NASA-JPL, overlain by a color airphoto Mosaic hosted at CubeWerx, with a road layer from USGS and the MVD project site information.

Resources OGC: –Specifications, discussion papers, news, links to product info –Contact information –Member pages OGC Network: ogcnetwork.org Open source products –UMN WMS: mapserver.gis.umn.edu –MIT Orthoserver (a WMS designed for orthophotos and imagery): –GeoServer (WFS):