Geography Markup Language (GML)

Geography Markup Language (GML) is an XML grammar for expressing geographical features. GML serves as a modeling language for geographic systems as well as an open interchange format for geographic transactions on the Internet. As with most XML based grammars, there are two parts to the grammar – the schema that describes the document and the instance document that contains the actual data. A GML document is described using a GML Schema. This allows users and developers to describe generic geographic data sets that contain points, lines, and polygons. However, the developers of GML envision communities working to define community-specific application schemas [] that are specialized extensions of GML. Using application schemas, users can refer to roads, highways, and bridges instead of points, lines, and polygons. If everyone in a community agrees to use the same schemas they can exchange data easily and be sure that a road is still a road when they view it. Clients and servers with interfaces that implement the OpenGIS® Web Feature Service Interface Standard [] read and write GML data. GML is also an ISO standard (ISO 19136:2007) [ ]. See also the GML pages on OGC Network: . Find out more at

OGC Geo4NIEM Testbed

Validate and provide recommendations to enhance National Information Exchange Model (NIEM) 3.0 architecture related to the Intelligence Community (IC) data encoding specifications (i.e., ISM, NTK, and TDF) aligned to Open Geospatial Consortium's (OGC) Testbed 9 work.

Provide recommendations to enable full-round-tripping from NIEM information exchange packages (IEP) to Geography Markup Language (GML) features and back to provide a comprehensive view of NIEM and GML capabilities and to document NIEM architectural gaps. 

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Incident Management Information Sharing (DHS S&T)

Current systems that are implemented to support the emergency management community are typically developed using proprietary data models that may inhibit information sharing. The IMIS Framework recommends an architecture where standard information encodings and standard data services are implemented in the IMIS-compliant systems to support the necessary data exchanges and improve overall interoperability between systems holding information and systems supporting consumers of the information.

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