GEMPAK Manual | Programs | Parameters


     GAREA is the graphics area.  This is the area which will be displayed 
     on a graphics device.

     GAREA can be specified in the following:

     1.  lat1;lon1;lat2;lon2 
         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.

     2.  GEOG
         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.

     3.  STN
         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
         the area.

     4.  Graphically using the CURSOR command.

     Note that the other ways of specifying AREA are not valid for GAREA.   
     For all projections, the lat/lon corners defined will be used exactly.
     (If GAREAX is used with the CURSOR command, the display area attempts 
     to fill the entire view area, extending the area defined by the selected 
     lat/lon).  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. If the projection has been 
     rotated so that a geographic pole is no longer at the center and 
     lat1 = lat2 and lon1 = lon2, then lat1 will determine the range of data 
     from the rotated pole and lon1 specifies the central longitude as before.
     If a cylindrical equidistant projection has been rotated for any angle1 
     between 90 and -90 degrees, then the entire world can be displayed 
     by entering GAREA=0;0;0;0. The central longitude is taken from the 
     PROJ specification for angle2. This works for angle1 = 0 as well.

     West longitude is negative.

     For overlay on satellite and radar imagery, PROJ must be set to
     SAT and RAD, respectively.