[gdal-dev] Problem with +ellps=airy which is used for BNG

Andreas Joisten mail at andreas-joisten.de
Tue Mar 23 06:42:06 EDT 2010

Hi all,

The BNG (British Natial Grid) based on the airy Ellipsoid but GDAL did not know this parameter.

+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs 

Probably, gdal does not know this parameter:  +ellps=airy

But gdal know these parameter:
ellipsoid_code	ellipsoid_name
7001	                 Airy 1830
7002	                 Airy Modified 1849

When I try to convert a Geotiff file from BNG to WGS84, I get an exception according to the ellipsoid.

Thanks for your help.

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