When geographically mapping data, for business or (unlikely) pleasure, a common file format used is the ESRI “shapefile”, typically recognised by ending with .shp. This file format allows one to specify custom polygons, with associated data. For instance, the counties of the United Kingdon, the territories of your business, or the areas covered by sales reps - anything effectively 2-dimensional. Alongisde the polygon spec you can store data – an obvious example being the name of the county in case 1 above.

What is less joyous though is generally the packages that handle these files with any form of style and grace are not free, or even cheap. There are some freeish viewers of various quality out there but if you wish to automate any sort of activity on these often gigantic files then usually it doesn’t come cheap. However, the Poorhouse did discover a free GIS program called MapWindow which is probably not a bad program in itself, but most usefully it contains a free GIS ActiveX control complete with API. This means you can link to it with any application that can interact programmatically with such things, not least the Microsoft Office applications suite.