DESCRIPTION
File map is used as reference file.
Cells in the mask are marked as "mask out" if the corresponding cell in
map contains a value in the range specified with maskvalues.
Before a new 3D-mask can be created the exisitng mask has to be removed
with g.remove.
SEE ALSO
g.remove
AUTHORS
Roman Waupotitsch, Michael Shapiro,
Helena Mitasova, Bill Brown, Lubos Mitas,
Jaro Hofierka
Last changed: $Date$