[Liblas-devel] Support for Variable Length Records

[Martin (OpenGeoMap)]

Howard Butler wrote:
> All,
>
> Building on some work by Mateusz, I have added support for VLRs to 
> libLAS.  The most useful application of this support is the reading 
> and writing of georeferencing information for LAS files, but it also 
> allows us to carry forward VLRs as part of a LiDAR processing chain 
> that includes programs like las2las.  The VLRs are carried around as 
> part of the LASHeader, and you interact with them as if they are 
> another header data member.
>
> Frank Warmerdam helped us out with parsing and reading the 
> georeferencing information, and there is now a LASHeader::GetProj4 
> method that you can use to return the spatial reference of a LAS file 
> that has VLRs describing the georeferencing information (actually, 
> we've found very few of these files even though the spec says that all 
> LAS files should have spatial referencing in the form of geotiff 
> keys).  To utilize GetProj4, you must link a cvs head version of 
> libgeotiff to libLAS with the --with-geotiff configure-time switch.
>
> Because we also support linking with GDAL, I plan to implement a 
> GetWKT() (or similarly named) method to the LASHeader that will 
> support ESRI SRS WKT operations.
>
> I think we should do a 0.9.7 release to provide the VLR and 
> georeferencing work for people to test.  We need some good testing of 
> this development with a wide variety of LAS files because the changes 
> were a bit disruptive.
Where can we put las files?
perhaps a private FTP account. by mail it's something like difficult, 
don't you think?

>
> Howard
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