[gdal-dev] OSGB36 to WGS84 transformation

[Johnny]

Thanks Hermann, 

Hermann Peifer <peifer at gmx.eu> writes:

> The lower left corner coordinates of the SD square are:
> 300 000 metres East
> 400 000 metres North
>
> So your test coordinate is at (Easting Northing): 380150 402109
>
> echo "380150 402109" | gdaltransform -s_srs EPSG:27700 -t_srs EPSG:4326
> -2.30083027968938 53.5152719980087 48.8662291513756
>

This led me to understand how to do the transformation based on the
easting northings derived from the OSGB definition and it then gives the
expected result. From [1] I get the explanation of the converstion of
the squares. 

Are you aware of any way to batch process this in Linux to enable swift
conversion of multiple references? 

> Please note that behind the scenes, these datum shift parameters are
> applied: +towgs84=375,-111,431,0,0,0,0 (which might be what you want
> .. or not).

Sorry, I don't know much about cartography and datums, but guess these
are the defaults by gdaltransform? Anyhow, it achieves what I want! :)


Regards,

Johnny

Footnotes: 
[1]  http://digimap.edina.ac.uk/webhelp/os/gazetteer_plus/grid_ref_conversion.htm

-- 
Johnny