[GRASS-dev] GRASS - UDig projection definitions

[Moritz Lennert]

On 12/02/07 14:10, Andrea Antonello wrote:
> Thanks Moritz,
> this also means that there is no easy way (something like parse that and
> that and then create the WTK), the proj pack has to be there, right?

You might be able to get a better idea by looking at

Check GPJ_grass_to_osr in lib/proj/convert.c
and
OSRExportToWkt in the proj source code.

But I'm really no expert on this.

Moritz

> 
> Andrea
> 
> 
> 
> Moritz Lennert probaly wrote:
>> On 12/02/07 13:58, Andrea Antonello wrote:
>>> Hi developers,
>>> I'm trying to make udig speak the same language as GRASS, but I found
>>> one main issue, I'm not able to resolve.
>>>
>>> GRASS and UDig use different projection definitions.
>>> - in Grass the projection file is something like:
>>>       name: Transverse Mercator
>>>       proj: tmerc
>>>       datum: rome40
>>>       towgs84: -225.000,-65.000,9.000
>>>       a: 6378388
>>>       es: 0.0067226700
>>>       lat_0: 0
>>>       lon_0: 9
>>>       k: 0.999600
>>>       x_0: 1500000
>>>       y_0: 0
>>>       no_defs: defined
>>>
>>> - whereas in UDig it is WKT:
>>>       PROJCS["Monte Mario / Italy zone 1",
>>>       GEOGCS["Monte Mario",
>>>       DATUM["Monte_Mario",
>>>       SPHEROID["International 1924", 6378388.0, 297.0,
>>> AUTHORITY["EPSG","7022"]],
>>>       AUTHORITY["EPSG","6265"]],
>>>       PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]],
>>>       UNIT["degree", 0.017453292519943295],
>>>       AXIS["Lon", EAST],
>>>       AXIS["Lat", NORTH],
>>>       AUTHORITY["EPSG","4265"]],
>>>       PROJECTION["Transverse_Mercator"],
>>>       PARAMETER["central_meridian", 9.0],
>>>       PARAMETER["latitude_of_origin", 0.0],
>>>       PARAMETER["scale_factor", 0.9996],
>>>       PARAMETER["false_easting", 1500000.0],
>>>       PARAMETER["false_northing", 0.0],
>>>       UNIT["m", 1.0],
>>>       AXIS["x", EAST],
>>>       AXIS["y", NORTH],
>>>       AUTHORITY["EPSG","3003"]]
>>>
>>> I'm no projection wizard, has anyone an idea about how I can go from one
>>> to the other and back in an easy way?
>>
>> g.proj -w  "Print projection information in WKT format"
>>
>> Moritz
>>