change extended classification

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Juan Lopez Bojorquez

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Sep 20, 2017, 6:03:44 PM9/20/17
to LAStools - efficient tools for LiDAR processing

I am trying to change_classification_from 0 to 40 and from 9 to 42.
When I do that, it create a new class 0 with the total number of records that were on class 0 and class 9.
When I tried to create a new las files, keeping all the class I need, but class 0,  it came empty.
When I tried to drop class 0, it drops class 40 and 42 as well.
I am using Las version 1.4
Andy idea how can I solve my problem?

Thanks,
Juan

Martin Isenburg

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Sep 20, 2017, 8:54:18 PM9/20/17
to LAStools - efficient command line tools for LIDAR processing
Hello Juan,

it would help if you could include a lasinfo report of the LAS files [1] from before and after your conversion as well as the exact las2las (?!?) command line that you used for conversion.

Regards,

Martin


PS: Want to meet rapidlasso GmbH in person and talk LiDAR, photogrammetry points and LAStools? See our upcoming schedule here: http://rapidlasso.com/events


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Juan Lopez Bojorquez

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Sep 21, 2017, 11:04:58 AM9/21/17
to LAStools - efficient tools for LiDAR processing
Thanks Martin for your message.

Please see the Before and after Las report of one file and the script I used.
********************
::Allows to run LASTools from any drive location
path=c:\lastools\bin

Las2las    -i  LAS14\*.las -change_extended_classification_from_to 9 40 -change_extended_classification_from_to 0 42 -set_extended_overlap_flag 1 -set_extended_scanner_channel 2
********************************

Thanks,
Juan
Before.jpg
After.jpg

cai...@vicforests.com.au

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Sep 28, 2017, 3:22:57 AM9/28/17
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Hi Martin,

Our current las file format is 1.3 but i need a format 1.2 las file.

How can i get a right format las file


Regards
Cai Li  I  GIS Analyst, Resources  I  VicForests

Level 12, 461 Bourke Street, Melbourne  Vic  3000  I  G P O Box 191, Melbourne   Vic   3001
T:  +61 03 9608 9571  I   F:  +61 03 9608 9566  I  E:  cai...@vicforests.com.au
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David Friedrich

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Sep 28, 2017, 10:53:55 AM9/28/17
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Hi Cai,

well with las2las for example you have the option -set_version 1.2.
For this basic question the readme files are gold. You will find them inside the bin folder. 
Every module brings its own readme.

Cheers,
David

------ Originalnachricht ------
Gesendet: 27.09.2017 21:53:10
Betreff: [LAStools] How to change las format from 1.3 to 1.2

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Martin Isenburg

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Sep 30, 2017, 6:20:13 AM9/30/17
to LAStools - efficient command line tools for LIDAR processing
Hello,

the most efficient way to "downgrade" a LAS 1.3 file to a LAS 1.2 file would be to simply rewrite the version number in the LAS header *in-place* (i.e. without rewriting the file) as 1.2 using the corresponding '-set_version 1.2' option in lasinfo [1]. This will result in a valid LAS 1.2 when your files are using point type 0, 1, 2, or 3.

lasinfo -i lidar\*.laz -set_version 1.2 -nc -nv 


Regards,

Martin @rapidlasso

PS: Want to meet rapidlasso GmbH in person and talk LiDAR, photogrammetry points and LAStools? See our upcoming event schedule here: http://rapidlasso.com/events




Martin Isenburg

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Sep 30, 2017, 10:17:42 AM9/30/17
to LAStools - efficient command line tools for LIDAR processing
Hello,

I think all is good just that the reporting of (an older version of) lasinfo confuses you. For all extended_classifications of 32 or higher the legacy classification was not just set to zero but also counted as zero in the histogram. I believe that this was fixed in the later versions of LAStools. Below a similar example:
 
:: creating a LAS 1.4 file

las2las -i ..\data\fusa.laz -set_point_type 6 -o fusa14.laz

:: this is how it looks now

lasinfo -i fusa14.laz
lasinfo (170915) report for fusa14.laz
reporting all LAS header entries:
  file signature:             'LASF'
  file source ID:             0
  global_encoding:            0
  project ID GUID data 1-4:   00000000-0000-0000-0000-000000000000
  version major.minor:        1.4
  system identifier:          'LAStools (c) by rapidlasso GmbH'
  generating software:        'las2las (version 170915)'
  file creation day/year:     40/2010
  header size:                375
  offset to point data:       469
  number var. length records: 1
  point data format:          6
  point data record length:   30
  number of point records:    0
  number of points by return: 0 0 0 0 0
  scale factor x y z:         0.01 0.01 0.01
  offset x y z:               0 0 0
  min x y z:                  277750.00 6122250.00 42.21
  max x y z:                  277999.99 6122499.99 64.35
  start of waveform data packet record: 0
  start of first extended variable length record: 0
  number of extended_variable length records: 0
  extended number of point records: 277573
  extended number of points by return: 263413 13879 281 0 0 0 0 0 0 0 0 0 0 0 0
variable length header record 1 of 1:
  reserved             43707
  user ID              'LASF_Projection'
  record ID            34735
  length after header  40
  description          'by LAStools of Martin Isenburg'
    GeoKeyDirectoryTag version 1.1.0 number of keys 4
      key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
      key 3072 tiff_tag_location 0 count 1 value_offset 32754 - ProjectedCSTypeGeoKey: WGS 84 / UTM 54S
      key 3076 tiff_tag_location 0 count 1 value_offset 9001 - ProjLinearUnitsGeoKey: Linear_Meter
      key 4099 tiff_tag_location 0 count 1 value_offset 9001 - VerticalUnitsGeoKey: Linear_Meter
LASzip compression (version 3.1r0 c3 50000): POINT14 3
reporting minimum and maximum for all LAS point record entries ...
  X            27775000   27799999
  Y           612225000  612249999
  Z                4221       6435
  intensity          10      62293
  return_number       1          3
  number_of_returns   1          3
  edge_of_flight_line 0          0
  scan_direction_flag 0          0
  classification      1          6
  scan_angle_rank    79        103
  user_data           0        197
  point_source_ID     1          1
  gps_time 5880.963028 5886.739738
  extended_return_number          1      3
  extended_number_of_returns      1      3
  extended_classification         1      6
  extended_scan_angle         13167  17167
  extended_scanner_channel        0      0
number of first returns:        263413
number of intermediate returns: 283
number of last returns:         263370
number of single returns:       249493
overview over extended number of returns of given pulse: 249493 27232 848 0 0 0 0 0 0 0 0 0 0 0 0
histogram of classification of points:
           17553  unclassified (1)
          180868  ground (2)
           37030  high vegetation (5)
           42122  building (6)

:: modify the LAS file

las2las -i fusa14.laz ^
            -change_extended_classification_from_to 6 40 ^
            -change_extended_classification_from_to 1 42 ^
            -set_extended_overlap_flag 1 ^
            -set_extended_scanner_channel 2 ^
            -odix _mod -olaz

:: this is how it looks now after the modifications

lasinfo -i fusa14_mod.laz
lasinfo (170915) report for fusa14_mod.laz
reporting all LAS header entries:
  file signature:             'LASF'
  file source ID:             0
  global_encoding:            0
  project ID GUID data 1-4:   00000000-0000-0000-0000-000000000000
  version major.minor:        1.4
  system identifier:          'LAStools (c) by rapidlasso GmbH'
  generating software:        'las2las (version 170915)'
  file creation day/year:     40/2010
  header size:                375
  offset to point data:       469
  number var. length records: 1
  point data format:          6
  point data record length:   30
  number of point records:    0
  number of points by return: 0 0 0 0 0
  scale factor x y z:         0.01 0.01 0.01
  offset x y z:               0 0 0
  min x y z:                  277750.00 6122250.00 42.21
  max x y z:                  277999.99 6122499.99 64.35
  start of waveform data packet record: 0
  start of first extended variable length record: 0
  number of extended_variable length records: 0
  extended number of point records: 277573
  extended number of points by return: 263413 13879 281 0 0 0 0 0 0 0 0 0 0 0 0
variable length header record 1 of 1:
  reserved             43707
  user ID              'LASF_Projection'
  record ID            34735
  length after header  40
  description          'by LAStools of Martin Isenburg'
    GeoKeyDirectoryTag version 1.1.0 number of keys 4
      key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
      key 3072 tiff_tag_location 0 count 1 value_offset 32754 - ProjectedCSTypeGeoKey: WGS 84 / UTM 54S
      key 3076 tiff_tag_location 0 count 1 value_offset 9001 - ProjLinearUnitsGeoKey: Linear_Meter
      key 4099 tiff_tag_location 0 count 1 value_offset 9001 - VerticalUnitsGeoKey: Linear_Meter
LASzip compression (version 3.1r0 c3 50000): POINT14 3
reporting minimum and maximum for all LAS point record entries ...
  X            27775000   27799999
  Y           612225000  612249999
  Z                4221       6435
  intensity          10      62293
  return_number       1          3
  number_of_returns   1          3
  edge_of_flight_line 0          0
  scan_direction_flag 0          0
  classification      0          5
  scan_angle_rank    79        103
  user_data           0        197
  point_source_ID     1          1
  gps_time 5880.963028 5886.739738
  extended_return_number          1      3
  extended_number_of_returns      1      3
  extended_classification         2     42
  extended_scan_angle         13167  17167
  extended_scanner_channel        2      2
number of first returns:        263413
number of intermediate returns: 283
number of last returns:         263370
number of single returns:       249493
overview over extended number of returns of given pulse: 249493 27232 848 0 0 0 0 0 0 0 0 0 0 0 0
histogram of classification of points:
          180868  ground (2)
           37030  high vegetation (5)
 +-> flagged as extended overlap: 277573
histogram of extended classification of points:
           42122  extended classification (40)
           17553  extended classification (42)
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