[Liblas-devel] Liblas-devel Digest, Vol 79, Issue 1

[Alexandre Guyot]

Hi Martin,


The output of lasinfo is at the bottom of my message.
Actually, I've also done it with the '-histo user_data' switch and I get an output confirming your point (average of ~38.4 for the user_data field = an average HAG of 3.8m) :
-->
user data histogram with bin size 0
 bin [0,0) has 994185
 average user data 38.4314 for 994185 element(s) <--
So the issue seems to come from my use of the libLAS python API for which I only get a "user_data = 2" for all my points.
I am simply doing :
from liblas import file
cloud = file.File(las_file, mode='r')
for point in cloud :
    print(point.user_data)
There's probably something I'm not getting.
Cheers,Alex 


------------------
reporting all LAS header entries:
  file signature:             'LASF'
  file source ID:             1321
  global_encoding:            0
  project ID GUID data 1-4:   00000000-0000-0000-0000-000000000000
  version major.minor:        1.2
  system identifier:          'LAStools (c) by rapidlasso GmbH'
  generating software:        'lasclassify (160921) unlicensed'
  file creation day/year:     296/2015
  header size:                227
  offset to point data:       229
  number var. length records: 0
  point data format:          1
  point data record length:   28
  number of point records:    994185
  number of points by return: 865554 116711 11586 341 0
  scale factor x y z:         0.01 0.01 0.01
  offset x y z:               0 0 0
  min x y z:                  597225.00 5331425.00 -6.10
  max x y z:                  597500.00 5331675.00 67.05
the header is followed by 2 user-defined bytes
LASzip compression (version 2.4r1 c2 50000): POINT10 2 GPSTIME11 2
reporting minimum and maximum for all LAS point record entries ...
  X            59722500   59750000
  Y           533142500  533167500
  Z                1206       6705
  intensity           1       4085
  return_number       1          4
  number_of_returns   1          4
  edge_of_flight_line 0          1
  scan_direction_flag 0          1
  classification      1          6
  scan_angle_rank   -10          2
  user_data           0        255
  point_source_ID   212        213
  gps_time 293715.352716 294035.308603
number of first returns:        865554
number of intermediate returns: 11938
number of last returns:         865515
number of single returns:       748822
WARNING: for return 2 real number of points by return (116706) is different from header entry (116711).
WARNING: for return 3 real number of points by return (11585) is different from header entry (11586).
WARNING: for return 4 real number of points by return (340) is different from header entry (341).
overview over number of returns of given pulse: 748822 210241 33761 1361 0 0 0
histogram of classification of points:
          224735  unclassified (1)
          358860  ground (2)
          342265  high vegetation (5)
           68325  building (6)user data histogram with bin size 0
 bin [0,0) has 994185
 average user data 38.4314 for 994185 element(s)
------------------

      De : Martin Isenburg <martin.isenburg at gmail.com>
 À : Alexandre Guyot <alexguyot at yahoo.fr> 
Cc : Howard Butler <howard at hobu.co>; "Van Dyke, Daryl" <daryl_van_dyke at fws.gov>; "Liblas-devel at lists.osgeo.org" <liblas-devel at lists.osgeo.org>
 Envoyé le : Mercredi 9 novembre 2016 22h45
 Objet : Re: [Liblas-devel] Liblas-devel Digest, Vol 79, Issue 1
  
Hi,
We created lasinfo so you can share an overview of the contents of LAS / LAZ files without having to send the whole file ...
lasinfo -i sample.laz -odix _info -otxt 
http://rapidlasso.com/lasinfohttp://lastools.org/download/lasinfo_README.txthttp://www.liblas.org/utilities/lasinfo.html

Regards,
Martin

   
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