I have had success plotting data indicators on a map with associated labels and alt text information as well as html links to more information using drawmap - spot the monk! . The program use GD.pm.

The code would need modification for a specific project.

You would need a map of your area in geographic projection and you would need to know the lat and long that correspond to the north, south, east, and west edges of your map in order to change a few of the calculations in the program. Some of the calculations need to be changed because the program assumes the map being used is one of the entire world with the prime meridian in the center of the map.

Assuming you are familiar with latitude and longitude, once you understand how the program works it's not hard to modify to a specific area of the world.

Good luck.