OGC Seeks Input On Web Mapping Standard

Wayland, MA, USA, December 13, 1999: The Open GIS Consortium, Inc. (OGC) today issued Requests for Comment on its pending OpenGIS Web Map Server Interface Specification and OpenGIS Geography Markup Language (GML) Specification.The OpenGIS Web Map Server Interface Specification provides a set of open protocols that will make it possible for users of ordinary web browsers to obtain and automatically overlay “map layers” of the same geographic region, where each layer is a “view” into geographic data potentially held by a different web server. Map servers can be from different vendors, and they can vary widely in terms of processing capabilities and data type (including multiple vector and raster types). The three protocols are relatively simple, and it is not difficult in most cases to add them to data servers. GetCapabilities provides information about what a server can do. GetMap gets maps, which might be georeferenced images (such as JPEG and PNG), simple display graphics (such as SVG or WebCGM), or more universally displayable “picture element” data (Simple Features XML, also known as GML). GetFeature_info provides information about features, so that users can query to get attributes of specific geographic features in a map layer.GML is a method for encoding OpenGIS Simple Features (basic vector-based geographic data) in XML. XSLT “stylesheets” can then be used to render this “smart data” in application-specific ways. The GML draft document will be submitted to W3C as a Note.In the OpenGIS Web Mapping Testbed, the Web Map Server was used with catalog services defined in the OpenGIS Catalog Services Specification, which provides a common architecture for online automated directories or registries of web-based geospatial data and geoprocessing services, rather like “spatial search engines.”As vendors implement these open standards in software, and as online geodata suppliers make their data available, web users will easily find, view, overlay, and combine different thematic maps for a given region.Geospatial data includes digital maps (including individual map elements such as roads, lakes and political boundaries), Earth images, and database records with street addresses or other fields that indicate physical location. Much geospatial data is currently available on the web, but users must posses considerable expertise and special geographic information system (GIS) software to overlay or otherwise combine different “map layers” of the same geographic region. Now, consensus among GIS software vendors in OGC has made it possible for such overlays and combinations of complex and essentially different kinds of geographic information to happen automatically over the Internet, despite differences in the vendors' geographic data storage, analysis, and display systems.The OpenGIS Technical Document 99-077 titled, “Web Map Server Interface Specification” was submitted by BBN Technologies (Cambridge MA), Cadcorp Ltd. (UK), CubeWerx Inc. (Canada), Ionic Software s.a. (Belgium), Laser-Scan Ltd. (UK), SICAD Geomatics GmbH & Co. oHG. (Germany), Social Change Online Pty Ltd. (Australia), and the US Army Engineer Research and Development Center (Alexandria, VA). The OpenGIS Technical Document 99-082r1 titled “Geography Markup Language (GML)” was submitted by Galdos Systems, Inc. (Canada), Oracle Corp. (Redwood Shores, CA), MapInfo Corp. (Troy, NY), Compusult, Ltd (Canada), and CubeWerx (Canada). Both documents are available for comment at http://www.opengeospatial.org/info/techno/request.htm .After the OGC Technical Committee reviews and incorporates comments, these specifications are likely to be formally adopted (as a single specification) at the OGC Technical Committee and Management Committee meetings to be held in Vancouver, BC in February, 2000.OGC is an international, not-for-profit organization working toward integration of geospatial capabilities into the world's information systems.– end –“