[pdal] Trouble reading some 3DEP tiles in PDAL

[Adam Steer]

Hi all
I appreciate the approach of PDAL reporting what is wrong and saying 'nope,
not proper las' - currently I'm working on a small project where that is
important feedback to a vendor.

The issue I can see around this style of hard rejecting a dataset is that
forensic data examination is ...difficult.

For example 'PDAL: readers.las: Extra byte specification exceeds point
length beyond base format length.' leads to lots of reading and guesswork,
because I can't actually interrogate the data without knowing to use other
tools. The current workaround is LASpy -> PDAL. If it helps to know, LASpy
reads in then writes the same files out as LAS which passes PDAL checks. I
should get around to closing that loop today (ie reporting what is
different about the LASpy-written lasfile).

Yes everyone in the lidar loop should check that their data are properly
LAS compliant before publishing. It doesn't happen, that's how it is.

What are the issues around pdal -info saying 'nope, not proper las' and
spewing out at least the header and some point data anyway?

Thanks,

Adam
--
Dr. Adam Steer
https://spatialised.net
0480441166







On Fri, Sep 13, 2024, 01:15 Andrew Bell via pdal <pdal at lists.osgeo.org>
wrote:

> lasinfo reports more information on these, but PDAL is correctly
> telling you what is wrong.
>
> On Thu, Sep 12, 2024 at 11:11 AM Andrew Bell <andrew.bell.ia at gmail.com>
> wrote:
> >
> > I believe that PDAL is correctly reporting these files as invalid.
> >
> > On Wed, Sep 11, 2024 at 3:00 PM Jim Klassen via pdal
> > <pdal at lists.osgeo.org> wrote:
> > >
> > > I'm getting errors reading some 3DEP tiles with "pdal info".  There
> are several of each type, but this is trimmed to one example of each.  My
> main question is if these are invalid LAZ files and/or is there an issue
> with the PDAL LAZ reader.   Tried with pdal 2.7.1 and 2.8.0.
> > >
> > > USGS_LPC_MN_BeckerCounty_2021_D21_264_5209.laz :  PDAL: readers.las:
> Extra byte specification exceeds point length beyond base format length.
> > > USGS_LPC_MN_BeckerCounty_2021_D21_265_5209.laz :  PDAL: readers.las:
> Invalid file signature. Was expecting 'LASF', Check the first four bytes of
> the file.   (this one looks corrupt)
> > > USGS_LPC_MN_SE_Driftless_2021_B21_4195_49005.laz :  PDAL: readers.las:
> Invalid version 1468 found in LAZ chunk table.
> > > USGS_LPC_MN_SE_Driftless_2021_B21_4480_49125.laz :  PDAL: readers.las:
> Invalid version 1464 found in LAZ chunk table.
> > >
> > > Source Files:
> > >
> https://rockyweb.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/MN_BeckerCounty_2021_D21/MN_BeckerCo_1_2021/LAZ/USGS_LPC_MN_BeckerCounty_2021_D21_264_5209.laz
> > >
> > >
> https://rockyweb.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/MN_BeckerCounty_2021_D21/MN_BeckerCo_1_2021/LAZ/USGS_LPC_MN_BeckerCounty_2021_D21_265_5209.laz
> > >
> > >
> https://rockyweb.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/MN_SE_Driftless_2021_B21/MN_SEDriftless_5_2021/LAZ/USGS_LPC_MN_SE_Driftless_2021_B21_4195_49005.laz
> > >
> > >
> https://rockyweb.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/MN_SE_Driftless_2021_B21/MN_SEDriftless_5_2021/LAZ/USGS_LPC_MN_SE_Driftless_2021_B21_4480_49125.laz
> > > _______________________________________________
> > > pdal mailing list
> > > pdal at lists.osgeo.org
> > > https://lists.osgeo.org/mailman/listinfo/pdal
> >
> >
> >
> > --
> > Andrew Bell
> > andrew.bell.ia at gmail.com
>
>
>
> --
> Andrew Bell
> andrew.bell.ia at gmail.com
> _______________________________________________
> pdal mailing list
> pdal at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/pdal
>
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