Non-interoperable Systems Phase Out

The fourth annual GML and Geo-Spatial Web Services Conference (formerly GML Days) took place in Vancouver, BC, Canada from 18th to 22nd July. The two days of workshops and the three-day conference focused on technical implementations of GML. Topics included GML and service-oriented architecture, dynamic publishing of cadastral data on the Web using GML model schemas, and ontology and spatial metaphor. The conference has attracted a growing number of attendees, indicating the increasing acceptance of GML.

The OpenGIS Geography Markup Language Encoding Specification (GML 3.1.1) defines a data encoding in XML, an XML ‘namespace’, for geographic data and its attributes. GML provides a means of encoding spatial information for both data transport and data storage, especially within a Web context.

Is it a good thing from the perspective of MapInfo Corporation, the Open Geospatial Consortium Inc. (OGC) and the Organization for the Advancement of Structured Information Standards (OASIS) that Google, Yahoo, Microsoft and AOL have entered the mapping field? Is it a good thing, given that two of the search-engine competitors, Google and Yahoo don’t use geospatial standards? (Microsoft's TerraServer USA serves maps through an interface that implements OGC OpenGIS Web Map Service Implementation Specification (WMS)http: //terraserverusa.com/ About.aspx?n=AboutWhatsNew&b=Update6_3).

Keynotes
The chief technical officer of MapInfo Corporation, OGC chief executive officer, and the director of standards development for OASIS presented keynotes at separate sessions. All three want to see standards adopted, but all three welcomed the opportunities that come with search-engine companies’ entry into the geospatial information market. "MapInfo revenue has doubled since AOL bought MapQuest," said George Moon of MapInfo. "Google, Yahoo and Microsoft want mind-share for Web search. They are not trying to own the mapping space – they want the search space." David Schell of OGC noted that "The New York Times finally discovered mapping last Sunday. The world is finally beginning to understand the value of geospatial analysis in the enterprise." James (Jamie) Clark of OASIS explained that failure to conform to standards was to be expected in the early stages of implementation and competition. OASIS, itself a standards body, is currently transitioning the location components of its Common Alert Protocol to use GML, developed in OGC and ISO TC 211.

GML Complex
Leslie Armstrong, deputy staff director of the US Federal Geographic Data Committee, explained US federal government efforts to create standard data models for Framework Data: "The UML (Unified Modeling Language) models will be transitioned to GML when the standards are complete. Those systems that cannot be made interoperable will be phased out," she said.
The panel discussion on the last day was on the topic, ‘GML: Too complex or just right?’ which has long been a subject of debate. Don Murray of SAFE Software proposed that any file format more complex than that which could be easily represented in a relational database was too much. Ron Lake, Galdos, one of the editors of the GML specification in OGC, countered that it was written to be capable of doing much, much more than simply pass data files. Lake explained that profiles and application schemas and tools to develop both are being written and that they will help developers use GML to satisfy their specific needs.