[pdal] "Unknown" values in WKT string

[Howard Butler]

Alexandre,

Would it be possible to (privately) inspect the file? PDAL transits the WKT through GDAL/PROJ, and it hands off all production and consumption to that. The entity names on the WKT are unknown because they don't match entries in the database that PROJ is using. It would be helpful to know what PROJ version you are using, but anything current is likely to have this behavior.

Also, which software produced this file?

Howard

> On Sep 4, 2020, at 4:32 AM, Alexandre Poirot <alexandre.poirot at pix4d.com> wrote:
> 
> Hello all,
> 
> I am trying to understand a behaviour of PDAL 2.1.0 regarding LAS file reading.
> 
> I have a LAS 1.4 file which have the following content as its WKT string:
> 
> ----------
> COMPD_CS["NAD83(2011) / Alabama West + Ellipsoid
> (Meters)",PROJCS["NAD83(2011) / Alabama
> West",GEOGCS["NAD83(2011)",DATUM["NAD83_National_Spatial_Reference_System_2011",SPHEROID["GRS
> 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","1116"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","6318"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",30],PARAMETER["central_meridian",-87.5],PARAMETER["scale_factor",0.999933333],PARAMETER["false_easting",600000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["X",EAST],AXIS["Y",NORTH],AUTHORITY["EPSG","6356"]],VERT_CS["Ellipsoid
> (Meters)",VERT_DATUM["Ellipsoid",2002],UNIT["metre",1.0,AUTHORITY["EPSG","9001"]],AXIS["Up",UP]]]
> -----------
> 
> I got this file from a colleague.
> 
> When I run the command (configuration: Archlinux with Linux 5.8 kernel):
> 
> ----------
> pdal info --metadata <myfile>
> ----------
> 
> I obtain the following result for the spatial reference:
> 
> ----------
> "spatialreference": "COMPD_CS[\"unknown\",PROJCS[\"NAD83(2011) /
> Alabama West\",GEOGCS[\"NAD83(2011)\",DATUM[\"NAD83_National_Spatial_Reference_System_2011\",SPHEROID[\"GRS
> 1980\",6378137,298.257222101,AUTHORITY[\"EPSG\",\"7019\"]],AUTHORITY[\"EPSG\",\"1116\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"6318\"]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"latitude_of_origin\",30],PARAMETER[\"central_meridian\",-87.5],PARAMETER[\"scale_factor\",0.999933333],PARAMETER[\"false_easting\",600000],PARAMETER[\"false_northing\",0],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AXIS[\"Easting\",EAST],AXIS[\"Northing\",NORTH],AUTHORITY[\"EPSG\",\"6356\"]],VERT_CS[\"unknown\",VERT_DATUM[\"unknown\",2005],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AXIS[\"Up\",UP]]]"
> ----------
> 
> I don't understand why and where the COMPD_CS, VERT_CS and VERT_DATUM
> are filled with "unknown" while it is defined in the LAS file.
> There is also some messages displayed in the console (6 to be thorough):
> "proj_uom_get_info_from_database: unit of measure not found"
> 
> So my first question is do you know why this behavior is happening?
> A second question is can I trust the point positions that PDAL read
> from the LAS file with the "unknown" being present in the srs?
> 
> Could "Ellipsoid" be a user defined coordinate system that my proj
> installation doesn't know?
> 
> Should I open an issue on the Github repository?
> 
> By the way, congratulations for the great work you've achieved so far
> on this library!
> 
> Best regards,
> Alexandre Poirot | Software Engineer
> Route de Renens 24 | 1008 Prilly, Switzerland
> alexandre.poirot at pix4d.com
> https://www.pix4d.com/
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