Defence Geospatial Information Working Group
About DGIWG

Background

The Defence Geospatial Information Working Group (DGIWG) was established in 1985 to foster the exchange of digital geospatial information (DGI). Initially, DGIWG was concerned only with the exchange of geographic data between independent national systems, hence, the DIgital Geographic Exchange STandard (DIGEST) was developed to enable this exchange to occur in a compatible manner. This standard went through several editions with the latest edition being published in September, 2000.

While the exchange of data sets between national systems was sufficient at first, the requirement to distribute data products directly to military end users became more important over time. DGIWG set out to develop data product specifications that were compliant with DIGEST by addressing various types of data. Imagery (raster data), elevation data (matrix data), and boundary data (vector data) were addressed in different parts of the DIGEST standard. The capability to handle different encoding for the same data content was also introduced in DIGEST. The main body of DIGEST (Part 2 of the DIGEST document) defined a data model that applied to all digital geographic information, and several annexes described the encoding of this data in different forms. These forms were:

  • A - Bulk interchange using the ISO 8211 data descriptive file format
  • B - Transaction and update using the ISO 8824/8825 telecommunication standard
  • C - Vector products using the Vector Relational Format corresponding to US MIL STD 2407
  • D - Imagery using the NATO Secondary Imagery Format corresponding to ISO 12087-5 BIIF

Recent developments in geospatial services have made obsolete the approach of defining data products in terms of an exchange format. Any portion of a broad suite of geospatial data needs to be dynamically accessible through a network. This situation has changed the approach taken by DGIWG. DIGEST is still retained for backward compatibility, but now information is defined in terms of an information content model, which can be expressed through an exchange format or through an application interface.