GRDAREA specifies the area to be covered by the grid. This area is
combined with PROJ to define the region over which the grid is evenly
GRDAREA can be specified in three ways:
This defines a latitude/longitude range where (lat1, lon1) is
the lower left corner and (lat2, lon2) is the upper right corner.
West longitude is negative.
This defines a latitude/longitude range by the center latitude
and longitude. The lower left corner is (clat-dlat; clon-dlon);
the upper right corner is (clat+dlat; clon+dlon). No corrections
are made for the poles or the International Date Line.
This is an abbreviation for a geographic area defined in the
GEMPAK geographic table which includes abbreviations for states,
provinces, and countries, as well as other names. A suffixed + or *
will decrease the extent of the geographic area. A suffixed - will
increase the extent of the geographic area.
This defines an area centered on a station found in the GEMPAK
station table, which currently contains US, Canadian and
Mexican stations. A suffixed + or * will expand, and - will reduce
Note that the other ways of specifying AREA are not valid for GRDAREA.
For all projections, the lat/lon corners defined will be used exactly.
For projections which include the pole, if lat1 = lat2 and lon1 = lon2,
then lat1 will specify the range of data from the pole and lon1 will
specify the central longitude. West longitude is negative.