Addition of circular arcs as a geometric primitive. (Annex C, C.220.127.116.11)
Addition of an optional z attribute parameter for geometric primitives, which provides a method of storing multiple z-values in select cases where disjoint z-values occur. (Annex C, C.18.104.22.168)
The use of the z attribute parameter in coordinates for geometric primitives to represent the elevation (special cases) at the location in a 2.5-D context. That is two-dimensional planar graph topology applies on a manifold in three dimensions. (The special cases and limitations have been defined for Annex C.)
Extension of feature relations (i.e., stack-on/stack-under), previously limited to the coverage level and the library level. (Annex C, C.22.214.171.124)
Addition of optional columns in the feature join table to support the storage of source information down to the feature and attribute level. (Annex C, C.126.96.36.199)
Defined standardized coded values commonly associated with attribute values (i.e., null, unknown). Provides encoding mechanism for non-coded attribute types. (Annex C, C.188.8.131.52)
Revision of DIGEST Part 2 Annex D "Image Interchange Format (IIF) Encapsulation Specification", to bring it into full alignment with the current editions of the NATO Secondary Imagery Format STANAG 4545 Edition 1 Amendment 1, the ISO 12087-5 Basic Image Interchange Format (BIIF) and the US National Imagery Transmission Format (NITF), MIL-STD 2500B Change Notice 1 and 2.
Replacement of Annex E with enhanced capabilities to support exchange of DIGEST information packages together with non-DIGEST set of files.
Clarification of the use of Not A Number (NAN) and special case enumerated values.