Using the field maps returned from the verification surveys, layers of changed habitat were created using ArcView. These were converted to ArcInfo format and used to update the Habitat Map.

For each habitat category, a GIS layer was created containing modifications to that category. These comprised:

• additions to the habitat (where the habitat was under classified); or

• deletions (where the habitat was mis/over-classified).

Additions to the habitat were treated by creating and coding polygons representing areas of the habitat, while deletions were treated by creating a polygon in the layer coded with the correct category.

An item indicating whether the habitat had been changed after surveying was added to the attribute table of the habitat map. The final habitat map is shown in Figure 9.1a.