Monday, September 15, 2014

OpenJUMP can color polygons with five colors

Larry Reeder made a plugin for coloring polygons according to the 5 color theorem  so that adjacent polygons do not have the same color. The Map Coloring plugin is pretty easy to use.







1) Open a polygon dataset

 


2) Find the tool from the menu and run.




3) A new layer which is colored with five colors will be created. Initial, half-arbitrary coloring is applied automatically but the color index is also saved as an "autoclr" attribute which makes it possible to adjust colors later with the standard classification tools.





How to install


Map coloring plugin can be downloaded from
https://sourceforge.net/projects/ojmapcoloring/files/. Installation is done by unzipping the plugin into /lib/ext folder of OpenJUMP. Restart is needed if OpenJUMP was running.


Known issues


Map coloring plugin is currently at version 0.40 and it may have issues if the polygon layer contains thousands of polygons. Using 64-bit jre helps a  lot with memory issues.

Posted on 3:03 PM | Categories: