IGN French user Grid setup information.  (Michelin info below)

> Does anyone know what the grid system is on the 1:100,000 France
> Topo maps made by IGN?
> -----<


> for 1:25 000 map, but I suppose for 1:100 000 it's the same
> system.
>
> IGN use NTF datum (Nouvelle Triangulation de la France)
>
> on my GPS12, I use:
>     - POSITION FRMT: USER GRID
>     - MAP DATUM: USER (Clark 1880 ellipsoid, IGN modified)
>         DX: -168 mt
>         DY: -60 mt
>         DZ: +320 mt
>         DA: -112 mt
>         DF: -0.5473884
>     - original meridian is Paris and not Greenwich
>     - offset Paris is 2° 20' 14.025" east of Greenwich.
>     - angles are in grades : 100 grades = 90 degrees.
>
> Yves
> --
> 73's de F3UB
> N 47.47708° W 0.69014° [ ED50 ]
> N 47.47610° W 0.69146° [WGS84]
> 

For a Michelin Map:
> Following is answer that I have recently received from Michelin web site
>
> Projection system for French map at scale 1/200 000 (yellow series)
>
>      Projection : Bonne (Conical)
>      Ellipsoid : Plessis
>      Origin : 2°20'14" E (Paris), 48°51'36" N DX, DY, DZ in relation with
>      WGS 84
>      a = axis = 6376523 m
>      f = flattening = 0.0032400188611
>      DX = 1118 m
>      DY = 23 m
>      DZ = 66 m
>
>      These data are for map Nr 51 à 89, 230 à 246
>
> N43° 15' 08"
> E05° 33' 25"
>
> Brian Spearing <brian.spearing@tesco.net> a écrit dans le message :
> 377fdd18.8990845@news.tesco.net...
> >
> > I want to set a few waypoints before a holiday in France, but the
> > 1cm=2km Michelin maps have a grid marked in *gr* units. These seem to
> > be at 100km spacing for latitude, and less for longitude. I can't see
> > any connection with UTM lat/long but 50gr looks close to 45deg N and
> > zero easting goes through Paris. Amazingly the key on the maps gives
> > no information, neither does the Michelin web site. The IGN 1cm=1km
> > maps have the same grid but marked almost unreadably.
> > Can anyone enlighten me please?
> >
> > Brian.
> >