[gdal-dev] Guidance sought on using gdal-translate

Christopher Hunt huntc at internode.on.net
Sat Aug 16 05:54:39 EDT 2008

Thanks for your reply Frank.

On 16/08/2008, at 2:05 PM, Frank Warmerdam wrote:

> I believe EPSG:27700 is British National Grid which is a projected
> coordinate system based on the OSGB 1936 datum.  So you should
> ensure the provider means the dataset is actually in BNG, in addition
> to being based on OSGB 1936.
OK, will do.

> If you can get BNG coordinates then that is great.
I've asked so fingers crossed.

> If you can only
> get WGS84 or OSGB1936 lat/long coordinates then you can
> convert these to BNG using a program like cs2cs though that is
> a bit tricky.

Hopefully one last question on this though: the a_ullr parameters -  
given the a_srs spec of EPSG:27700, are the a_ullr parameters expected  
to be in BNG coordinates i.e. eastings and northings values? Asking  
this another way, what actually dictates the coordinate system used  
for the a_ullr parameters?


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