An overview of GML support in ArcGIS

The Open Geospatial Consortium, Inc.'s (OGC) Geography Markup Language (GML) Encoding Specification is a standard protocol for expressing geographic features, their geometries, and attributes using XML. GML has two key parts: an application schema that describes the GML document and the document that contains the actual data encoded using XML.

GML is a mechanism for encoding almost any geospatial schema. This capability supports the need for an organization to publish its own information model regardless of whether it is simple, rich, or somewhere in between.

GML was designed to be broad and cover many needs. For example, the GML 3 specification describes close to 1,000 tags (named objects) and incorporates a number of potential geometry types for describing features. These include simple or aggregate features, circular and elliptical arcs, 3D, topology, rasters, sensor feeds, metadata, and time-based features.

ESRI recommends use of the GML Simple Features profile for open information exchange. For users to openly share information across systems using an open profile, the chosen profile must be adopted by many organizations. The GML Simple Features profile was designed as a common format for interoperability by many GIS software organizations that are committed to providing support. We recommend the use of GML Simple Features where possible. ArcGIS includes direct converters to read, write, and serve GML Simple Features.

ArcGIS supports the creation and use of complex GML schemas using the optional Data Interoperability extension. ArcGIS also provides an optional suite of data conversion tools as part of the Data Interoperability extension. This extension supports the transfer of geographic data using a number of GML schemas.

The Data Interoperability extension to ArcGIS is based on Safe Software Inc.'s FME and includes the FME workbench, which interchanges data between hundreds of GIS, CAD, raster, and database formats and schemas. The Data Interoperability extension to ArcGIS can be used to define and use custom translators that can support more sophisticated GML schemas. For example, you can use this extension to add support to ArcGIS for your own GML schema.