set xflip on|off
'set lat 20 45'
'set lon 40 60'
'set xflip on'
' display u,v'
This is documentation for basemap.gs, a Grads script that overlays a land or ocean mask that exactly matches the coastal outlines of the three Grads map files: lowres, mres, and hires. Basemap works by overlaying polygons on top of an existing display; once they are all drawn, the polygons appear as a solid region that covers the land or ocean areas. Basemap does not actually mask the data, it only masks the display of the data.
basemap.gs L(and)/O(cean) <fill_color> <outline_color> <L(owres)/M(res)/H(ires)>
The land and ocean masks are composed of hundreds of polygons that are specified in accompanying ASCII files. The ASCII files must be downloaded from the Grads script library. Once you have downloaded these files and stored them in a convenient location, you must update your copy of basemap.gs to include the path of the location of these files. The script will not work without these files.
Grads is free software. Under the terms of the new COPYRIGHT, you can redistribute it and/or modify it under the terms of the GNU General Public License. Grads is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantibility or fitness for a particular purpose. The tables below contains links to the most recent releases. Be sure to download the appropriate tar file for your particular hardware and operating system. Older builds are available via ftp.
This function takes an areal average over an X-Y region. The syntax is:
aave(expr, xdim1, xdim2, ydim1, ydim2)
expr- any valid grads expression
xdim1- starting X dimension expression
xdim2- ending X dimension expression
ydim1- starting Y dimension expression
ydim2- ending Y dimension expression