[Liblas-devel] LAS file Coordinate Systems

[Howard Butler]

On Jul 23, 2009, at 1:39 PM, Patel, Ronak Avinash (US SSA) wrote:

> Howard and Mateusz,
>
> Thanks for the help...really appreciate it. Haven't really found many
> people out there that know the low levels as much as you guys do.
>
> I was looking at the LAS 1.2 spec and it says the Georeferencing
> information requires the GeoKeyDirectoryTag Record.
>
> I am able to write that tag out but I see that lasinfo always shows  
> the
> version to be 0.0.0 regardless of what I put in those fields.
>
> According to the spec, the data should be arranged:
>
> wKeyDirectoryVersion = 1 (2 bytes)
> wKeyRevision = 1 (2 bytes)
> wMinorRevision = 0 (2 bytes)
> wNumberOfKeys  = the number of sets of 4 unsigned shorts to follow
>
> I write out the above shorts and 0 out the rest of the data byte array
> but lasinfo always shows 0.0.0 as the version.
>
> Is the spec wrong? Or is something else going on here that lasinfo and
> libLAS are doing??

Are you linking libLAS with libgeotiff when you compile?  libLAS  
completely ignores georeferencing if libgeotiff is not linked at  
compile time.

Howard