[Liblas-devel] Retrieving User Data/Point source ID with LibLAS (python)

Aaron Reyna aaron.reyna at gmail.com
Wed Apr 7 11:17:04 EDT 2010


Thanks Howard,

So, does that mean that libLAS is incapable of extracting that information
based on it's current version? Maybe I didn't understand your reply.

I ran it the other night and looked at the results, it seems to be
correct. Striations could be seen in the raster I created that looked
similar to that in the intensity raster.

Oh, and it should be noted that only Raw .las files contain this information
in the User Data/Point Source Id. When those files are imported into
usable delineations and grounded, (as in, not per flight line) the Point Id
is written over with gps time.

Thanks for the help, I appreciate it!

aaron

On Tue, Apr 6, 2010 at 8:32 PM, Howard Butler <hobu.inc at gmail.com> wrote:

>
> On Apr 5, 2010, at 2:29 PM, Howard Butler wrote:
>
> >
> > On Apr 5, 2010, at 2:23 PM, Aaron Reyna wrote:
> >
> >> Hi everyone,
> >>
> >> I am wondering if anyone has come up with a way, or knows how to
> retrieve User Data/Point Source ID in a .Las 1.2 file,
> >
> > pt.user_data
> >
> > This will be byte data, however, and it is up to you to interpret this
> data into integers or whatever value the software that wrote the gain into
> the user data expects.
> >
> > You must join the liblas-devel list to properly post, and the discussion
> will continue there.
>
> This is wrong.  Only pt.user_data is available as of libLAS 1.2+.  I have
> added support in the latest development branch of libLAS Mercurial for
> pt.point_source_id
>
> Thanks for the report.  The note about how to interpret either of those
> data elements still stands, however.
>
> Howard
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