[Proj] Using cs2cs.

[Joshua Brown]

On 30/04/12 07:57, Hermann Peifer wrote:
> On 30/04/2012 05:54, Joshua Brown wrote:
>> Hello,
>>
>> I have a text file, with each OSGB32 value on a new line.
>>
>> I want to convert from OSGB32 to WGS84 so I can map values to google
>> earth.
>>
>> How can I use cs2cs to convert the text file into WGS84?
>>
> 
> I assume that with OSGB32 you actually mean: OSGB36. I have recently
> been using [1] and [2] for getting from OSGB36 to WGS84. [2] is the more
> accurate alternative. You can find a link to OSTN02_NTv2.gsb at the PROJ
> wiki page, see [3].
> 
> Hermann
> 
> [1]
> cs2cs -v -f "%.6f" +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717
> +x_0=400000 +y_0=-100000 +ellps=airy
> +towgs84=446.448,-125.157,542.06,0.15,0.247,0.842,-20.489 +to
> +proj=longlat +datum=WGS84
> 
> [2]
> cs2cs -v -f "%.6f" +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717
> +x_0=400000 +y_0=-100000 +ellps=airy +nadgrids=./OSTN02_NTv2.gsb  +to
> +proj=longlat +datum=WGS84
> 
> [3] http://trac.osgeo.org/proj/wiki

Thanks for the response,

Yes I do mean OSGB36 ... I think. I have National grid references in the
format "SH1234512456" that I need to convert.

I've had a go but I still don't think I understand the input and output
values.

Any help with this, much appreciated.