EPSG 6350 Albers Conic Equal Area

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gwb...@gmail.com

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Jun 11, 2018, 6:01:25 PM6/11/18
to LAStools - efficient tools for LiDAR processing
Hello,

I am trying to convert Laz files from NAD83(2011) / UTM zone 16N (epsg 6345) to NAD83(2011) / Conus Albers (epsg 6350) but the resulting data fall ~2500km south of true location.  I used both command lines below, the second with the understanding that the input file is recognized as UTMz16.  

I went through the codes in the PCS.csv file and find the projection parameters and epgs codes to be correct.  I also tried converting to epsg 5072 (NAD83(2007) / Conus Albers) but encounter the same issue.

I have no issues converting from 6345 to 6350 using other software.


las2las.exe -epsg 6345 -target_epsg 6350 -i *.laz -olaz -odix _EPSG6350

las2las.exe -i *.laz -target_epsg 6350 -olaz -odix _EPSG6350


Has anyone encountered similar issues?

Thanks

Gerry

Martin Isenburg

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Jun 12, 2018, 7:02:52 AM6/12/18
to LAStools - efficient command line tools for LIDAR processing
Hello,

it would be good to get a sample LAZ file to have a closer look. Please send a link to a file (do not attach it). 

Regards,

Martin

PS: It's always good to send a lasinfo report along with any question on miss-behaving LAS/LAZ files.

gwb...@gmail.com

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Jun 12, 2018, 2:37:07 PM6/12/18
to LAStools - efficient tools for LiDAR processing
Two LAZ files (channel 1 & 2) with lasinfo reports have been uploaded to the following FTP:

FTP Server:         ftp.airborneimaginginc.com

Username:         LasToolsFTP

Password:           laso55


Thank you,

Gerry

gwb...@gmail.com

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Jun 13, 2018, 6:00:14 PM6/13/18
to LAStools - efficient tools for LiDAR processing
Hi Martin,

Problem solved

las2las.exe -i *.LAZ -target_epsg 6350 -set_ogc_wkt -vertical_navd88 -set_ogc_wkt_in_evlr -olaz -odix _EPSG6350

The initial issue was how other software reads the projection information, not the actual conversion.  The EVLR maintained the NAD83(2011) UTMz16 WKT payload as well as the header.

With the command above using  -set_ogc_wkt_in_evlr the reference to NAD83(2011) UTMz16 is removed and now the header information is correct:

PROJ_DESC=Albers Conic / NAD83_NSRS / meters
PROJ_DATUM=NAD83 (NSRS2011)
PROJ_UNITS=meters
EPSG_CODE=EPSG:6350

However the EVLR now shows the OGC coordinate system as null:

extended variable length header record 1 of 1:
  reserved             0
  user ID              'LASF_Projection'
  record ID            2112
  length after header  0
  description          'by LAStools of rapidlasso GmbH'
    OGC COORDINATE SYSTEM WKT:
    (null)


Do I need to run the command -set_ogc_wkt_in_evlr in a separate batch to add the WKT payload to the EVLR?

I uploaded the output Lasinfo text files to the FTP.

Thank you

Gerry

Martin Isenburg

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Jun 27, 2018, 7:01:01 AM6/27/18
to LAStools - efficient command line tools for LIDAR processing
Hello,

I ***STRONGLY*** advise against the storage of the OGC WKT in the EVLR section of a LAS/LAZ file. For the reasoning behind this read these discussion threads:


It may look like a minor change but makes it impossible to implement efficient streaming / piping workflows for LAS/LAZ files.

========================

It's much easier to do tests with smaller (not 221 million points) files. Here how to create one (1 million points):

E:\LAStools\bin>las2las -i 621810113_1.laz ^
                                       -subseq 0 1000000 ^
                                       -odix _sub -olaz

And here the two re-projections. It may be worthwhile to update to the last version of LAStools as there was recently a small fix in the (bad, don't do it) EVLR storage of OGC WKT strings.

E:\LAStools\bin>las2las -i 621810113_1_sub.laz ^
                                       -target_epsg 6350 ^
                                       -vertical_navd88 ^
                                       -set_ogc_wkt ^
                                       -odix _EPSG6350 -olaz

E:\LAStools\bin>las2las -i 621810113_1_sub.laz ^
                                       -target_epsg 6350 ^
                                       -vertical_navd88 ^
                                       -set_ogc_wkt_in_evlr ^
                                       -odix _EPSG6350ext -olaz

============================================

E:\LAStools\bin>lasinfo.exe -i 621810113_1_sub.laz
lasinfo (180620) report for '621810113_1_sub.laz'
reporting all LAS header entries:
  file signature:             'LASF'
  file source ID:             0
  global_encoding:            17
  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 180620)'
  file creation day/year:     109/2018
  header size:                375
  offset to point data:       477
  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:               666485 3372595 53
  min x y z:                  666364.49 3372548.37 -90.16
  max x y z:                  667143.86 3372929.99 79.70
  start of waveform data packet record: 0
  start of first extended variable length record: 4709654
  number of extended_variable length records: 1
  extended number of point records: 1000000
  extended number of points by return: 745120 225092 28485 1292 11 0 0 0 0 0 0 0 0 0 0
variable length header record 1 of 1:
  reserved             0
  user ID              'LASF_Projection'
  record ID            34735
  length after header  48
  description          'by LAStools of rapidlasso GmbH'
    GeoKeyDirectoryTag version 1.1.0 number of keys 5
      key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
      key 3072 tiff_tag_location 0 count 1 value_offset 6345 - ProjectedCSTypeGeoKey: NAD83(2011) / UTM zone 16N
      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
      key 4096 tiff_tag_location 0 count 1 value_offset 5103 - VerticalCSTypeGeoKey: VertCS_North_American_Vertical_Datum_1988
extended variable length header record 1 of 1:
  reserved             0
  user ID              'LASF_Projection'
  record ID            2112
  length after header  863
  description          'by LAStools of rapidlasso GmbH'
    OGC COORDINATE SYSTEM WKT:
    COMPD_CS["NAD83(2011) / UTM zone 16N + NAVD88",PROJCS["NAD83(2011) / UTM zone 16N",GEOGCS["NAD83(2011)",DATUM["NAD_1983_2011",SPHEROID["GRS 1980",6378137,29
8.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","1116"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG
","9122"]],AUTHORITY["EPSG","6318"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-87],PARAMETER["scale_fact
or",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH]
,AUTHORITY["EPSG","6345"]],VERT_CS["NAVD88",VERT_DATUM["North American Vertical Datum 1988",2005,AUTHORITY["EPSG","5103"]],UNIT["metre",1.0,AUTHORITY["EPSG","90
01"]],AXIS["Gravity-related height",UP],AUTHORITY["EPSG","5703"]]]
LASzip compression (version 3.2r4 c3 50000): POINT14 3
reporting minimum and maximum for all LAS point record entries ...
  X              -12051      65886
  Y               -4663      33499
  Z              -14316       2670
  intensity       26192      59199
  return_number       1          5
  number_of_returns   1          5
  edge_of_flight_line 0          1
  scan_direction_flag 0          0
  classification      2          7
  scan_angle_rank    18         30
  user_data          62         62
  point_source_ID 10113      10113
  gps_time 207510079.885403 207510089.461827
  extended_return_number          1      5
  extended_number_of_returns      1      5
  extended_classification         2      7
  extended_scan_angle          3000   5000
  extended_scanner_channel        1      1
number of first returns:        745120
number of intermediate returns: 29596
number of last returns:         746757
number of single returns:       521473
overview over extended number of returns of given pulse: 521473 392288 81106 5081 52 0 0 0 0 0 0 0 0 0 0
histogram of classification of points:
          284062  ground (2)
          715681  medium vegetation (4)
             257  noise (7)

E:\LAStools\bin>lasinfo.exe -i 621810113_1_sub_EPSG6350.laz
lasinfo (180620) report for '621810113_1_sub_EPSG6350.laz'
reporting all LAS header entries:
  file signature:             'LASF'
  file source ID:             0
  global_encoding:            17
  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 180620)'
  file creation day/year:     109/2018
  header size:                375
  offset to point data:       1440
  number var. length records: 2
  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:               1000000 800000 0
  min x y z:                  1026356.70 880009.76 -90.16
  max x y z:                  1027133.12 880415.02 79.70
  start of waveform data packet record: 0
  start of first extended variable length record: 4709654
  number of extended_variable length records: 0
  extended number of point records: 1000000
  extended number of points by return: 745120 225092 28485 1292 11 0 0 0 0 0 0 0 0 0 0
variable length header record 1 of 2:
  reserved             0
  user ID              'LASF_Projection'
  record ID            34735
  length after header  48
  description          'by LAStools of rapidlasso GmbH'
    GeoKeyDirectoryTag version 1.1.0 number of keys 5
      key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
      key 3072 tiff_tag_location 0 count 1 value_offset 6350 - ProjectedCSTypeGeoKey: NAD83(2011) / Conus Albers
      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
      key 4096 tiff_tag_location 0 count 1 value_offset 5103 - VerticalCSTypeGeoKey: VertCS_North_American_Vertical_Datum_1988
variable length header record 2 of 2:
  reserved             0
  user ID              'LASF_Projection'
  record ID            2112
  length after header  909
  description          'by LAStools of rapidlasso GmbH'
    WKT OGC COORDINATE SYSTEM:
    COMPD_CS["NAD83(2011) / Conus Albers + NAVD88",PROJCS["NAD83(2011) / Conus Albers",GEOGCS["NAD83(2011)",DATUM["NAD_1983_2011",SPHEROID["GRS 1980",6378137,29
8.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","1116"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG
","9122"]],AUTHORITY["EPSG","6318"]],PROJECTION["Albers_Conic_Equal_Area"],PARAMETER["standard_parallel_1",29.5],PARAMETER["standard_parallel_2",45.5],PARAMETER
["latitude_of_center",23],PARAMETER["longitude_of_center",-96],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"
]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","6350"]],VERT_CS["NAVD88",VERT_DATUM["North American Vertical Datum 1988",2005,AUTHORITY["EPSG",
"5103"]],UNIT["metre",1.0,AUTHORITY["EPSG","9001"]],AXIS["Gravity-related height",UP],AUTHORITY["EPSG","5703"]]]
LASzip compression (version 3.2r4 c3 50000): POINT14 3
reporting minimum and maximum for all LAS point record entries ...
  X             2635670    2713312
  Y             8000976    8041502
  Z               -9016       7970
  intensity       26192      59199
  return_number       1          5
  number_of_returns   1          5
  edge_of_flight_line 0          1
  scan_direction_flag 0          0
  classification      2          7
  scan_angle_rank    18         30
  user_data          62         62
  point_source_ID 10113      10113
  gps_time 207510079.885403 207510089.461827
  extended_return_number          1      5
  extended_number_of_returns      1      5
  extended_classification         2      7
  extended_scan_angle          3000   5000
  extended_scanner_channel        1      1
number of first returns:        745120
number of intermediate returns: 29596
number of last returns:         746757
number of single returns:       521473
overview over extended number of returns of given pulse: 521473 392288 81106 5081 52 0 0 0 0 0 0 0 0 0 0
histogram of classification of points:
          284062  ground (2)
          715681  medium vegetation (4)
             257  noise (7)

E:\LAStools\bin>lasinfo.exe -i 621810113_1_sub_EPSG6350ext.laz
lasinfo (180620) report for '621810113_1_sub_EPSG6350ext.laz'
reporting all LAS header entries:
  file signature:             'LASF'
  file source ID:             0
  global_encoding:            17
  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 180620)'
  file creation day/year:     109/2018
  header size:                375
  offset to point data:       477
  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:               1000000 800000 0
  min x y z:                  1026356.70 880009.76 -90.16
  max x y z:                  1027133.12 880415.02 79.70
  start of waveform data packet record: 0
  start of first extended variable length record: 4659445
  number of extended_variable length records: 1
  extended number of point records: 1000000
  extended number of points by return: 745120 225092 28485 1292 11 0 0 0 0 0 0 0 0 0 0
variable length header record 1 of 1:
  reserved             0
  user ID              'LASF_Projection'
  record ID            34735
  length after header  48
  description          'by LAStools of rapidlasso GmbH'
    GeoKeyDirectoryTag version 1.1.0 number of keys 5
      key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
      key 3072 tiff_tag_location 0 count 1 value_offset 6350 - ProjectedCSTypeGeoKey: NAD83(2011) / Conus Albers
      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
      key 4096 tiff_tag_location 0 count 1 value_offset 5103 - VerticalCSTypeGeoKey: VertCS_North_American_Vertical_Datum_1988
extended variable length header record 1 of 1:
  reserved             0
  user ID              'LASF_Projection'
  record ID            2112
  length after header  909
  description          'by LAStools of rapidlasso GmbH'
    OGC COORDINATE SYSTEM WKT:
    COMPD_CS["NAD83(2011) / Conus Albers + NAVD88",PROJCS["NAD83(2011) / Conus Albers",GEOGCS["NAD83(2011)",DATUM["NAD_1983_2011",SPHEROID["GRS 1980",6378137,29
8.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","1116"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG
","9122"]],AUTHORITY["EPSG","6318"]],PROJECTION["Albers_Conic_Equal_Area"],PARAMETER["standard_parallel_1",29.5],PARAMETER["standard_parallel_2",45.5],PARAMETER
["latitude_of_center",23],PARAMETER["longitude_of_center",-96],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"
]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","6350"]],VERT_CS["NAVD88",VERT_DATUM["North American Vertical Datum 1988",2005,AUTHORITY["EPSG",
"5103"]],UNIT["metre",1.0,AUTHORITY["EPSG","9001"]],AXIS["Gravity-related height",UP],AUTHORITY["EPSG","5703"]]]
LASzip compression (version 3.2r4 c3 50000): POINT14 3
reporting minimum and maximum for all LAS point record entries ...
  X             2635670    2713312
  Y             8000976    8041502
  Z               -9016       7970
  intensity       26192      59199
  return_number       1          5
  number_of_returns   1          5
  edge_of_flight_line 0          1
  scan_direction_flag 0          0
  classification      2          7
  scan_angle_rank    18         30
  user_data          62         62
  point_source_ID 10113      10113
  gps_time 207510079.885403 207510089.461827
  extended_return_number          1      5
  extended_number_of_returns      1      5
  extended_classification         2      7
  extended_scan_angle          3000   5000
  extended_scanner_channel        1      1
number of first returns:        745120
number of intermediate returns: 29596
number of last returns:         746757
number of single returns:       521473
overview over extended number of returns of given pulse: 521473 392288 81106 5081 52 0 0 0 0 0 0 0 0 0 0
histogram of classification of points:
          284062  ground (2)
          715681  medium vegetation (4)
             257  noise (7)



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