[Proj] MapInfo coordsys to proj.4 syntax

Paul Surgeon surgpub at telkomsa.net
Tue Jun 6 04:04:56 EDT 2006

That helped a bit Anthony although it's not quite there yet.

I changed the false northing from 200000 to 2200000 because the MapInfo user 
created their own coordsys definition and didn't use a stock NTF one. Using 
the standard NTF false northing of 200000 shifts the data about 20 degrees 
too far to the North.

I tried :
gdal_translate -a_srs "+proj=lcc +lon_0=2.337229166667 +lat_0=46.8 
+lat_1=45.898918964419 +lat_2=47.696014502038 +x_0=600000 +y_0=2200000 
+a=6378249.2 +rf=293.4660213 +towgs84=-168,-60,320,0,0,0,0 +units=m +no_defs" 
temp1.tif temp2.tif

Now the raster data is only about 480 meters too far to the South and 48 
meters too far to the East (rough estimate).
So something still isn't quite right.


On Tuesday 06 June 2006 02:00, Anthony Dunk wrote:
> Hi Paul,
> NTF uses a prime meridian of 2.337229166667 (Paris), not Greenwich.
> Below is the correct PROJ string for converting from Lat/Lon WGS84 to
> projected NTF (French Lambert II Centre).
> cs2cs +proj=latlong +a=6378137.0 +rf=298.257223563 +towgs84=0,0,0 +to
> +proj=lcc +lon_0=2.337229166667 +lat_0=46.8 +lat_1=45.898918964419
> +lat_2=47.696014502038 +x_0=600000 +y_0=200000 +a=6378249.2
> +rf=293.4660213 +towgs84=-168,-60,320,0,0,0,0 +units=m +no_defs
> Using this an input point of 2.33333E, 48.8667N is projected to
> 599766.90 mE, 429819.60 mN. This agrees with MapInfo's projection of
> the same point.
> Anthony.

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