Status of GAP Components

This section reviews the status of the constituent parts, or components needed, to conduct Gap Analysis. Gap Analysis was begun with a focus on the terrestrial environment, however, the development of information and analyses must logically be extended to the aquatic environment; the aquatic component of Gap Analysis is also treated in this section. The status of analyses of the GAP data layers is discussed in the "Products" section of this report.

Metadata

Completing standard metadata for all of the GAP data layers is mandatory. The standards for GAP were developed by Cogan and Edwards (1994) in compliance with the Federal Geographic Data Committee (FGDC 1992, 1994), and the GAP standards are cited as an example by the FGDC (1995). Cogan and Edwards (1994) provide:

• content standards for Gap Analysis project metadata (58 data elements are covered);
• examples of metadata construction;
• examples of data dictionary entry;
• a default theme keyword thesaurus.

The GAP metadata standards continue to evolve, with the idea being that the FGDC requirements represent the minimum criteria for GAP. Minor revisions are being made to the GAP standards to comply with the final FGDC standards (1995). The FGDC standards are, in some cases, not sufficient to document some kinds of biological resource data, especially if they are of a non-spatial nature. For example, it may be important for a user to know about field sampling methods or changes to taxonomic classification. For this reason, the GAP metadata standards include a "Nonspatial File Format" element not required by the FGDC.

At the 1995 GAP annual meeting, a session was devoted to the use of the Arc/Info DOCUMENT tool in generating metadata. Emphasis was placed on recording metadata as original data layers are being constructed, rather than generating metadata as an afterthought. Further, it was recognized that the automated log files in Arc/Info are insufficient to track the lineage of data layer developments, and it is critical that technicians also maintain written records of their work. These records must include the commands used, the parameters for each command, and a short statement as to the logic of the process. The records can be kept in the "Overview_Description" text field provided in Arc/Info. The revisions to Cogan and Edwards (1994) will include these refinements.