Colouring the Political Map
Author: Forrest, David
Source: Cartographic Journal, The, Volume 33, Number 2, December 1996 , pp. 141-147(7)
Publisher: Maney Publishing
Abstract:Maps differentiating countries by colour are commonly used in atlases and elsewhere. A condition of such maps is that each zone should have a different colour from each of its neighbours. It has been proved that a minimum of four colours is necessary for this, although applying these colours to a set of zones is likely to be a process of trial and error until a satisfactory solution is found. The problem is analysed and the procedure for finding a solution is described. In order to automate the task the solution is implemented using PROLOG, a declarative language well suited to this type of problem.
Document Type: Short Communication
Publication date: December 1996