[Proj] MapInfo coordsys to proj.4 syntax

Paul Surgeon surgpub at telkomsa.net
Mon Jun 5 18:00:25 EDT 2006

I'm trying to convert a MapInfo coordinate system into something that proj.4 
understands but my high school maths doesn't seem to be helping me much.

The TAB files look like this :
(830000.00,2050000.00) (0,0) Label "Pt 1",
(840000.00,2050000.00) (2000,0) Label "Pt 2",
(840000.00,2040000.00) (2000,2000) Label "Pt 3",
(830000.00,2040000.00) (0,2000) Label "Pt 4"
CoordSys Earth Projection 
Units "m"

I've read some MapInfo docs and managed to break it down to :
Name of projection = CoordSys Earth Projection 3
Projection type = 3 = Lambert Conformal Conic
Datum = 1002 = NTF (Paris)
Ellipsoid = Modified Clark 1880
Units = 7 = meters
Origin lon = 0 (central meridian)
Origin lat = 46.8
Standard parallel 1 = 45.898918964419
Standard parallel 2 = 47.696014502038
False Easting = 600000
False Northing = 2200000

I tried to use one of the standard NTF (Paris) EPSG definitions as a base to 
work from but that doesn't seem to work.

My attempt :
+proj=lcc +lon_0=0.0 +lat_0=46.8 +lat_1=45.898918964419 +lat_2=47.696014502038 
+k_0=0.99987742 +x_0=600000 +y_0=2200000 +a=6378249.2 +b=6356515 
+towgs84=-168,-60,320,0,0,0,0 +pm=greenwich +units=m +no_defs

I assigned this srs definition with gdal_translate and then used gdalwarp to 
warp the raster into a standard UTM zone.
However I must be really far out with the proj.4 syntax because when I try to 
lay the resulting raster over another it's so far out that I can't identify 
anything common between the two images.

Any ideas where I'm going wrong?

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