Hi Laurent For one cave in the Dordogne, I used cs UTM31 The co-ordinates to fix the entrance were then read off from a UTM grid overlay on the digital (CD) version of the IGN map You may find this site helps http://www.geoportail.gouv.fr/accueil, though I seem to only be getting lat-Long or Lambert co-ordinates at present, not UTM Graham -- graham.mullan@coly.org.uk