begin wks = gsn_open_wks("png","color7") ; Open a png file "color7.png" ; ; Change the color map using a predefined color map. See: ; ; http://www.ncl.ucar.edu/Document/Graphics/color_table_gallery.shtml ; gsn_define_colormap(wks,"BlAqGrYeOrReVi200") ; gsn_draw_colormap(wks) ; Draw the color map. ; Note there's no gray. grays = NhlNewColor(wks,(/0.5,0.8/),(/0.5,0.8/),(/0.5,0.8/)) gsn_draw_colormap(wks) ; Draw the new color map ; You should see 2 grays colors. end