[Liblas-devel] 0.error: detail::liblas::read_n<T> input stream is not readable

[Peter Tittmann]

developers,

I'm having a weird problem with las2txt and i think las2las as well. I am
trying to subset this file (http://169.229.13.22/pub/LiDAR/ucd_04.las) using
the commands:

las2txt --delimiter " " --parse xyzRGBc -i ucd_04.las -o ~/Desktop/04_0.txt
-v -e "412725.875 4532149.5 412860.34375 4532359.5" --first-return-only
--keep-classes 1

which returns

Opening ucd_04.las to fetch Header
Keeping classes with the values: 1
---------------------------------------------------------
 Clipping file to the extent
---------------------------------------------------------
 minx: 412725.875000 miny: 4532149.500000 minz: 0.000000
 maxx: 412860.343750 maxy: 4532359.500000 maxz: 0.000000
---------------------------------------------------------
Keeping first returns only.
Setting precisions from header to 2 2 2 8
Using delimiter ' '
Writing points:
 - :
0.error: detail::liblas::read_n<T> input stream is not readable

if i remove the '--first-return-only' argument the command succeeds

las2las using the same coordinates succeeds with both arguments however when
using the 'first-returns-only' argument the resulting .las file has no
points.

las2las just clipping the file to the coordinates shows that there are first
returns within that region:

las2las -i ucd_04.las -o ~/Desktop/04_0.las -v -e "412725.875 4532149.5
412860.34375 4532359.5"
Opening ucd_04.las to fetch Header
---------------------------------------------------------
 Clipping file to the extent
---------------------------------------------------------
 minx: 412725.875000 miny: 4532149.500000 minz: 0.000000
 maxx: 412860.343750 maxy: 4532359.500000 maxz: 0.000000
---------------------------------------------------------
Writing output:
 - : /home/peter/Desktop/04_0.las
0...

and

$ lasinfo  ~/Desktop/04_0.las


lasinfo  ~/Desktop/04_0.las
---------------------------------------------------------
  Header Summary
---------------------------------------------------------

  Version:                     1.0
  Source ID:                   0
  Reserved:                    0
  Project ID/GUID:             '00000000-0000-0000-0000-000000000000'
  System ID:                   ''
  Generating Software:         'TerraScan'
  File Creation Day/Year:      0/0
  Header Byte Size             227
  Data Offset:                 229
  Number Var. Length Records:  None
  Point Data Format:           1
  Number of Point Records:     144379
  Compressed:                  False
  Number of Points by Return:  89804 42205 11178 1192 0
  Scale Factor X Y Z:          0.01 0.01 0.01
  Offset X Y Z:                -0.00 -0.00 -0.00
  Min X Y Z:                   412726.37 4532149.73 23.14
  Max X Y Z:                   412860.33 4532359.50 76.27
  Spatial Reference:           None

---------------------------------------------------------
  Schema Summary
---------------------------------------------------------
  Point Format ID:             1
  Number of dimensions:        13
  Custom schema?:              false
  Size in bytes:               28

  Dimensions
---------------------------------------------------------
  'X'                            --  size: 32 offset: 0
  'Y'                            --  size: 32 offset: 4
  'Z'                            --  size: 32 offset: 8
  'Intensity'                    --  size: 16 offset: 12
  'Return Number'                --  size: 3 offset: 14
  'Number of Returns'            --  size: 3 offset: 14
  'Scan Direction'               --  size: 1 offset: 14
  'Flightline Edge'              --  size: 1 offset: 14
  'Classification'               --  size: 8 offset: 15
  'Scan Angle Rank'              --  size: 8 offset: 16
  'User Data'                    --  size: 8 offset: 17
  'Point Source ID'              --  size: 16 offset: 18
  'Time'                         --  size: 64 offset: 20

---------------------------------------------------------
  Point Inspection Summary
---------------------------------------------------------
  Header Point Count: 144379
  Actual Point Count: 144379

  Minimum and Maximum Attributes (min,max)
---------------------------------------------------------
  Min X, Y, Z: 412726.37, 4532149.73, 23.14
  Max X, Y, Z: 412860.33, 4532359.50, 76.27
  Bounding Box: 412726.37, 4532149.73, 412860.33, 4532359.50
  Time: 589039.231020, 589422.198199
  Return Number: 1, 4
  Return Count: 1, 4
  Flightline Edge: 0, 0
  Intensity: 1, 860
  Scan Direction Flag: 0, 1
  Scan Angle Rank: -12, 13
  Classification: 1, 2
  Point Source Id: 16017, 16019
  User Data: 32, 32
  Minimum Color (RGB): 0 0 0
  Maximum Color (RGB): 0 0 0

  Number of Points by Return
---------------------------------------------------------
(1) 89804 (2) 42205 (3) 11178 (4) 1192

  Number of Returns by Pulse
---------------------------------------------------------
(1) 47367 (2) 62012 (3) 30178 (4) 4822

  Point Classifications
---------------------------------------------------------
130234 Unclassified (1)
14145 Ground (2)
  -------------------------------------------------------
   0 withheld
   0 keypoint
   0 synthetic

Thanks very much for any guidance you can provide.

best,

Peter Tittmann
UC Davis Geography Graduate Group
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