The Digital Geographic Information Exchange Standard (DIGEST) was developed by the DGIWG (previously known as the Digital Geographic Information Working Group) to support efficient exchange of Digital Geographic Information among nations, data producers, and data users. It was designed as a “family of standards” capable of supporting the exchange of multiple data types (e.g. vector). DIGEST was first published in June 1991 with the release of Edition 1.0. It underwent a number of revisions and was last issued in September 2000 with the release of Edition 2.1.

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 DIGEST standard is divided into 4 parts:

  • Part 1 is a brief General Description of the standard.
  • Part 2 consist of Theoretical Model, Exchange Structure, Encapsulation Specifications (Annexes A through D) and a Standard ASCII Table of Contents (Annex E).   The Part 2 encapsulations include: Annex A  – Bulk interchange using the ISO 8211 data descriptive file format; Annex B – Transaction and update using the ISO 8824/8825 telecommunication standard; Annex C – Vector products using the Vector Relational Format corresponding to U.S. MIL-STD-2407; Annex D – Imagery using the NATO Secondary Imagery Format corresponding to ISO 12087-5, Basic Imagery Interchange format (BIIF)
  • Part 3 consists of Codes and Parameters
  • Part 4 is a Feature and Attribute Coding Catalogue (FACC) Data Dictionary

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.

DIGEST is no longer maintained by DGIWG but is provided here because legacy systems are still operating that are based on this standard.

DGIWG NumberDoc TypeTitle
001DIGEST 2.1 Part 1 General Description
002DIGEST 2.1 Part 2 Theoretical Model Exchange Structure and Encapsulation Spec
003DIGEST 2.1 Part 2A ISO 8211 Encapsulation Specification
004DIGEST 2.1 Part 2B ISO 8824 Encapsulation Specification
005DIGEST 2.1 Part 2C Vector Relational Format
006DIGEST 2.1 Part 2D Image Interchange Format
007DIGEST 2.1 Part 2D Image Interchange Format Errata
008DIGEST 2.1 Part 2E Standard ASCII Table of Contents
009DIGEST 2.1 Part 3 Codes and Parameters
010DIGEST 2.1 Part 4 Annex A Feature Codes
011DIGEST 2.1 Part 4 Annex B Attribute and Value Codes
012DIGEST 2.1 Part 4 Annex C Alphabetized Content Listing of all Features and Attributes
013DIGEST 2.1 Part 4 FACC
014DIGEST Support Document 1 – Geodesy Background Notes
015DIGEST Support Document 2 -Table of Encoding Options for Geographic Entities
016DIGEST Support Document 3 – The ARC System