[Liblas-devel] liblas writing proj4 string (using python api)

[Howard Butler]

On Jun 4, 2009, at 7:47 PM, Wes Toews wrote:

> hi Howard,
>
> Thanks for your quick reply.
>
> Hmmm makes sense - that's a good exception to trigger!
>
> I'm using the PyPI plugins, but that makes sense now that you  
> mention it that the OSGeo would be more inclusive.  Does your newer  
> s.proj4 by any chance record an EPSG code in the VLR?

No.  proj4 strings are not very transitive, and you will loose things  
like EPSG codes if you use them as part of the translation.  You need  
to use WKT to i/o your spatial reference systems in that case.  The  
only way to do that is by linking in GDAL support to libLAS.  The  
OSGeo4W distribution has GDAL linked into it.  Otherwise, you would  
have to compile it yourself.


> And I'm guessing that since there's no 1.2 API for python (or C# for  
> that matter)

There is as libLAS 1.2 version of the Python API available http://pypi.python.org/pypi/libLAS/1.2.0 
  and from OSGeo4W.  The place to go for examples of how to use it is  
the doctests.  (see the .txt files here http://liblas.org/browser/trunk/python/tests 
  )

The C# bindings for libLAS *have not* been updated to include the new  
SRS handling, however.



> I'll have to put together something that calls the liblas binaries  
> from python for the SRS handling? (or is there an 'unofficial'  
> release of the 1.2 API?).
>
> I'll let you know how it all works in any case.
>

I have taken the liberty of replying to the liblas-devel list for  
anyone else who might have the same trouble.

Hope this helps,

Howard