

r.clump - 

r.clump finds all areas of contiguous cell \category values\ in the
input user-specified raster map layer.  It assigns a unique category
value to each such area ("clump") in the resulting output raster map
layer.  If the user does not provide input and output map layer
names on the command line, the program will prompt the user for these
names.

Manual entry for \r.clump\
