This collection of auxilliary files can be used with the datafiles to create
special views of the information, or to provide annotation. The "masks"
can be used with the Saga GIS program to delete grid information on either the
land or water.
The above figure is of the 1-km landmask, where water (blue) has a value of
1 and land (white) has a value of 0; the same convention holds true for all
landmasks. Watermasks have a value of 0 for water and 1 for land.
This convention accords with the Saga GIS software. Other systems may
reverse this convention, in which case the user should simply switch files.