Coverage rebuilding is a boundary operation to create new coverages that are identified and selected by users.
Boundary operations include the following six commands.
- Clip: to identify and preserve features within the boundary of interest specified by users. It is called a "cookie cutter".
- Erase: to erase features inside the boundary while preserving features outside the boundary.
- Update : to replace features within the boundary by cutting out the current polygons and pasting in the updated polygons.
- Split: to create new coverages by clipping geographic features with divided borders.
- Append: to merge the same feature classes of points and lines from the adjacent coverages.
- Map Join: to join the adjacent polygon features into a single coverage and to rebuild to topology. It is called mosaicking.
Figure 4.5 shows the concept of coverage rebuilding.