All mapping software programmes use the same base maps, and the majority will run on multiple platforms. But they all use proprietary interfaces. So once you've made your choice you're locked in. It's the old Nikon/Canon, Ford/GM conversation. So you may want to take a look at additional functionality.

I happen to use Anquet, which I bought way back '02. But Memory Map is an excellent product. Make sure, however, that you can consolidate all your individual (day) routes into a single route that takes in the whole of your Challenge, and that you can then print this out as a series of pages with, for example, a 5% overlap. I've found that I can usually get my route onto around sixteen pages.

But the real fun begins once you've finalised your route and then use your digital mapping software's output to fly over your Challenge.

Export your consolidated route as a large (typically around 5MB) GPX file. And then convert this to KMZ format and import the result into Google Earth. You can now use Google Earth's Tour function to fly over your entire Challenge, oh yea! I set this up so I'm 100m above ground level, with the camera at 80 degrees.

It took about half-an-hour to fly from Strathcarron to Stonehaven, and gave a terrific overview of the terrain. If anyone would like detailed instructions send me an eMail off-forum.

Memory Map and Anquet both offer the French IGN 1:25000 mapping - I've used Anquet extensively in the field in both the French Pyrenees and French Alps, using an Android smartphone.