The FF writer creates and writes feature data to the FF file specified by the DATASET directive. Any FF file with the same name is overwritten with the new feature data.
Tip: Tip: It is important to mention that polygons can be written out in two different methods.
If a polygon feature is written out with a closed area as its geometry, the topology for this feature will be computed and all the appropriate pieces will be written to the FF file automatically. The second method of writing out polygons is to compute the topology before hand and write out each piece separately. In this method polygons will have no geometry, but will have the appropriate up and down links to the edges and centroid features, as necessary.