[Gdal-dev] help with adding a projection definition

[Jim Klassen]

I ran into this recently with UMN Mapserver as the application.

It appears that GDAL and PROJ both have a copy of the projection  
information. The solution was to add the well known text description  
of the coordinate system to epsg.wkt file (as well as the proj file)

Thanks to Frank W. for pointing this out to me on the Mapserver list.

As an example, I changed our epsg.wkt to read:

include esri_extra.wkt
include cubewerx_extra.wkt

200068,PROJCS["MN Ramsey County", GEOGCS["NAD83 (1986)", DATUM["GRS  
1980 + MN Ramsey Elevation", SPHEROID["Unknown", 
6378418.941,298.2572242549219]], PRIMEM["Greenwich",0], UNIT["Degree", 
0.017453292519943295]], PROJECTION["Lambert_Conformal_Conic_2SP"],  
PARAMETER["standard_parallel_1",45.13333333333333], PARAMETER 
["standard_parallel_2",44.88333333333333], PARAMETER 
["latitude_of_origin",44.79111111111111], PARAMETER 
["central_meridian",-93.38333333333334], PARAMETER["false_easting", 
500000], PARAMETER["false_northing",100000], UNIT["Foot_US", 
0.30480060960121924]]

And added the following to the epsg file for proj4:

<200068> +proj=lcc +lat_2=44.88333333333333 +lat_1=45.13333333333333  
+lat_0=44.79111111111111 +lon_0=-93.38333333333334 +x_0=152400.3048  
+y_0=30480.0610 +unit=sft +to_meter=0.30480060960122 +a=6378418.941  
+b=6357033.310 +no_defs <>


On Jun 30, 2006, at 4:40 PM, TC Haddad wrote:

> I'd like to use gdalwarp to reproject some large geotiffs, but
> apparently my projection of choice EPSG:4495 is not recognized by
> gdal.
>
> On a previous machine I had to edit an old version of proj4 to take
> this EPSG code, and was successful at that time. The parameters were
> as follows:
>
> # NAD83 / Oregon Lambert (Intl ft)
> <4495> +proj=lcc +lat_1=43 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5
> +x_0=400000.00000 +y_0=0 +ellps=GRS80 +datum=NAD83 +to_meter=0.3048
> no_defs <>
>
> I'd like to do the same again, but I can't figure out where gdal is
> getting it's projection definitions from... what file name should I be
> looking for?
>
> My situation is FWtools 1.0.0b2 installed on WinXP sp2
>
> thanks for any help,
>
> Tanya
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Jim Klassen
City of Saint Paul
Public Works Computer Services
(651) 266-6098