# plmeridians.3plplot man page

**plmeridians** — Plot latitude and longitude lines

## Synopsis

**plmeridians**(*mapform*, *dlong*, *dlat*, *minlong*, *maxlong*, *minlat*, *maxlat*)

## Description

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

Redacted form: **plmeridians(mapform, dlong, dlat, minlong, maxlong, minlat, maxlat)**

This function is used in example 19.

## Arguments

*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.

## Authors

Many developers (who are credited at http://plplot.sourceforge.net/credits.p…) have contributed to PLplot over its long history.

## See Also

PLplot documentation at http://plplot.sourceforge.net/documenta….

## Info

PLplot API August, 2015