Region masks based on state boundaries. state-polys.txt has (semi-low-res) lat/lon coordinates for each state. Taken from XML file found online at http://econym.org.uk/gmap/states.xml Edited by hand in emacs to tabular state-lat-lon format Then we generate a file containing just the lat & lon for each state polygon as follows: mkdir poly-coords foreach i (`cut -f 1 state-polys.txt | uniq`) echo $i grep $i state-polys.txt | cut -f 2- > poly-coords/$i.txt end Create proto.nc from existing mask files and fill up with blank. Note: change fill/missing to 1e20 to match data & get ncbo to work properly. Then just edit & run maskgen.ncl to create a new mask file.