---
name: "plmeridians"
section: "3plplot"
platform: "linux"
package: "plplot-doc"
version: "5.15.0+dfsg2-15"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/plmeridians"
---

# plmeridians(3plplot)

Plot latitude and longitude lines

## NAME

**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* (**PLMAPFORM\_callback**(3plplot), 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**(3plplot), input)

  The interval in degrees at which the longitude lines are to be plotted.

- *dlat* (**PLFLT**(3plplot), input)

  The interval in degrees at which the latitude lines are to be plotted.

- *minlong* (**PLFLT**(3plplot), 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**(3plplot), input)

  The value of the longitude on the right side of the plot.

- *minlat* (**PLFLT**(3plplot), 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**(3plplot), 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.org/credits.php) have contributed to PLplot over its long history.

## SEE ALSO

PLplot documentation at http://plplot.org/documentation.php.