The problem with precombined maps (especially country specific maps, which we have in abundance already) is that you cannot easily go beyond the boundaries of those maps. Before creating this service I had a few scenario’s in my mind which I wanted to make as easy as possible for the common computer user.
Travel through multiple countries:
So if you plan a trip to go skiing and therefore travel from The Netherlands through Germany and Switserland to Austria you will need four maps, combine them yourself in MapSource and then upload to the GPS.
Locality:
If you live close to a border you might be interested in downloading parts of more then one country. Others might just rarely travel far and are therefore perhaps only interested in downloading and using a small portion of the map.
This service allows you to just select the tiles you’re interested in and wait until the combining is finished. The combining is rather easy when the splitting of the planet file is done and the Garmin maps have been created. This needs to happen anyway, even if you distribute prebuilt combined maps. Zipping the maps for individual requests isn’t that hard (if it wasn’t for the server to be busy with my other projects too). Creating custom maps saves bandwidth but costs more in CPU power and disk space, but of those I have (currently) enough.
I do think about creating prebuilt downloads for entire continents besides this service though, as there is probably somewhere an optimal point where flexibility meets ease of use, CPU power and disk space…