Tif error with las2dem

[Dave Munger]

Hello,

I am currently generating the DTM in tif format of several tiles of a Lidar project in batch with las2dem. The command is:

las2dem -i * .laz -keep_classification 2 -step 0.7 -kill 200 -elevation -extra_pass -use_tile_bb -otif

Occasionally, I'm not able to open the tif with ArcGIS 10.4.1. It's freezing and I have to crash it.

However, when I go to treat the tile in problem only everything works and I am able to open the tile. So example:

las2dem -i "E: \ tiles \ tile_375200_5621000.laz" -keep_classification 2 -step 0.7 -kill 200 -elevation -extra_pass -use_tile_bb -otif

What can make it work in this case and not in the other?

Thank you !

[Martin Isenburg]

Hello Dave,

without addressing the root of the problem ... but it may be if you run on multiple cores (add '-cores 2' to the end of the command line) the issue may go away (and you may run at twice the speed across your folder of files).

Regards.

Martin @rapidlasso 

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[Dave Munger]

Hello Martin,

This was missing in my example. When I process multiple tiles at the same time I was already in -core 8 mode. The crazy thing is that Lastools works normally and the tif is produced. I can even open it in an image editor, but not in ArcGis ...

Thank you !

[Martin Isenburg]

Hello Dave,

it would be good if you could share such an "odd" TIFF. The good one and the bad one. Maybe running gdalinfo (like lasinfo but for any raster file) will already give you / me already enough of a clue ... ?

http://www.gdal.org/gdalinfo.html

Regards,

Martin @rapidlasso

[Dave Munger]

Great, here is result for :

Bad:

Driver: GTiff/GeoTIFF

Files: tuile_375200_5621000.tif

       tuile_375200_5621000.tfw

Size is 2000, 2000

Coordinate System is:

LOCAL_CS["NAD83(CSRS) / MTM zone 6 | GRS 1980",

    GEOGCS["NAD83",

        DATUM["unknown",

            SPHEROID["GRS 1980",6378137,1,

                AUTHORITY["EPSG","7019"]],

            AUTHORITY["EPSG","6617"]],

        PRIMEM["Greenwich",0],

        UNIT["degree",0.0174532925199433],

        AUTHORITY["EPSG","4269"]],

    AUTHORITY["EPSG","2948"],

    UNIT["metre",1]]

Origin = (375200.000000000000000,5622400.000000000000000)

Pixel Size = (0.700000000000000,-0.700000000000000)

Metadata:

  AREA_OR_POINT=Area

  TIFFTAG_ARTIST=created by LAStools (c) martin....@rapidlasso.com

  TIFFTAG_SOFTWARE=LAStools is a product of rapidlasso GmbH, Germany

Image Structure Metadata:

  COMPRESSION=LZW

  INTERLEAVE=BAND

Corner Coordinates:

Upper Left  (  375200.000, 5622400.000)

Lower Left  (  375200.000, 5621000.000)

Upper Right (  376600.000, 5622400.000)

Lower Right (  376600.000, 5621000.000)

Center      (  375900.000, 5621700.000)

Band 1 Block=2000x20 Type=Float32, ColorInterp=Gray

  NoData Value=-9999

  

Good:

Driver: GTiff/GeoTIFF

Files: tuile_375200_5621000.tif

       tuile_375200_5621000.tfw

Size is 2000, 2000

Coordinate System is:

LOCAL_CS["NAD83(CSRS) / MTM zone 6 | GRS 1980",

    GEOGCS["NAD83",

        DATUM["unknown",

            SPHEROID["GRS 1980",6378137,298.2572221010002,

                AUTHORITY["EPSG","7019"]],

            AUTHORITY["EPSG","6617"]],

        PRIMEM["Greenwich",0],

        UNIT["degree",0.0174532925199433],

        AUTHORITY["EPSG","4269"]],

    AUTHORITY["EPSG","2948"],

    UNIT["metre",1]]

Origin = (375200.000000000000000,5622400.000000000000000)

Pixel Size = (0.700000000000000,-0.700000000000000)

Metadata:

  AREA_OR_POINT=Area

  TIFFTAG_ARTIST=created by LAStools (c) martin....@rapidlasso.com

  TIFFTAG_SOFTWARE=LAStools is a product of rapidlasso GmbH, Germany

Image Structure Metadata:

  COMPRESSION=LZW

  INTERLEAVE=BAND

Corner Coordinates:

Upper Left  (  375200.000, 5622400.000)

Lower Left  (  375200.000, 5621000.000)

Upper Right (  376600.000, 5622400.000)

Lower Right (  376600.000, 5621000.000)

Center      (  375900.000, 5621700.000)

Band 1 Block=2000x20 Type=Float32, ColorInterp=Gray

  NoData Value=-9999

There is a difference in the projection...

Thank !

Dave

[Dave Munger]

Here is the file :

https://drive.google.com/drive/folders/1Bn-sxT4zUdw-0ReKumDSfKTMOv0E6g98?usp=sharing

Thank !