plmeridians: Plot latitude and longitude lines

DESCRIPTION

Displays latitude and longitude on the current plot. The lines are plotted in the current color and line style.

Redacted form: General: plmeridians(mapform, dlong, dlat, minlong, maxlong, minlat, maxlat) F95, Java, Perl/PDL, Python: Not implemented?

This function is used in example 19.

mapform (void (*) (PLINT, PLFLT *, PLFLT *), input): A user supplied function to transform the coordinate longitudes and latitudes to a plot coordinate system. By using this transform, we can change from a longitude, latitude coordinate to a polar stereographic project, for example. Initially, x[0]..[n-1] are the longitudes and y[0]..y[n-1] are the corresponding latitudes. After the call to mapform(), x[] and y[] should be replaced by the corresponding plot coordinates. If no transform is desired, mapform can be replaced by NULL.
dlong (PLFLT, input): The interval in degrees at which the longitude lines are to be plotted.
dlat (PLFLT, input): The interval in degrees at which the latitude lines are to be plotted.
minlong (PLFLT, input): The value of the longitude on the left side of the plot. The value of minlong must be less than the value of maxlong, and the quantity maxlong-minlong must be less than or equal to 360.
maxlong (PLFLT, input): The value of the longitude on the right side of the plot.
minlat (PLFLT, input): The minimum latitude to be plotted on the background. One can always use -90.0 as the boundary outside the plot window will be automatically eliminated. However, the program will be faster if one can reduce the size of the background plotted.
maxlat (PLFLT, input): The maximum latitudes to be plotted on the background. One can always use 90.0 as the boundary outside the plot window will be automatically eliminated.