GPS map datums for France

[duncster]

I have a GPS that i've been successfully using in the UK for a couple of years.

I'm touring in France this year and wondered:

what map datum do they use in France
what's the best maps to use...thinking probably michelin 1:150,000?

[piedwagtail91]

you should be able to find out off a michelin map if thats what you're using, you could always use WGS84 if lat and long are shown on the map, there is something called ntf but you'd need to check it's in your gps and is also used on the map. http://www.trackthisout.com/Grids.htm lists datums for various parts of france

[andrew_s]

French maps have always been fairly useless as far as referencing any position is concerned, with only a very coarse lat/long grid for guidance, and no hint on what the datum/projection might be. This has meant that the standard French way of telling someone where something is is to specify it a (eg Michelin 81, fold 7, 5.3cm from left, 12.3 from top (or something similar))

This page may be of use:
http://gpsinformation.net/main/igngrids.htm

I've also heard hints that the latest IGN maps are WGS84/UTM may have a reasonable grid. I'd suggest looking in a bookshop.
My most recent IGN is 2001 and is of the GPS-useless variety, as is a 2004 Michelin

[duncster]

thanks, gentlemen. very useful.

i knew the answer had to be on the www somewhere...