[Proj] OSTN02 question: GRS80 instead of Airy.
Frank Warmerdam
warmerdam at pobox.com
Mon Oct 30 15:04:40 EST 2006
Roger Oberholtzer wrote:
> No takers on this one?
>
> On Wed, 2006-10-25 at 12:58 +0200, Roger Oberholtzer wrote:
>> I use the C API to do transformations. I am converting from GPS values
>> in WGS84 to OSTN02 for the United Kingdom. My current code is:
>>
>> fromProj = pj_init_plus(
>> "+proj=latlong "
>> "+ellps=WGS84 "
>> "+towgs84=0,0,0 "
>> "+nodefs")
>>
>> toProj = pj_init_plus(
>> "+proj=tmerc "
>> "+lat_0=49 "
>> "+lon_0=-2 "
>> "+k=0.9996012717 "
>> "+x_0=400000 "
>> "+y_0=-100000 "
>> "+ellps=airy "
>> "+nadgrids=gb.gsb "
>> "+units=m "
>> "+no_defs")
>>
>> Note that I do a grid shift, using data provided by a kind member of
>> this list.
>>
>> My question is, how can I use the GRS80 ellipsoid instead of Airy?
Roger,
Well, you would just change +ellps=airy to +ellps=GRS80.
But perhaps your question was more subtle?
Best regards,
--
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I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org
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