las2las transform elevation data from ellipsoid geoid 18 ortho

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George S. Mercier

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Aug 9, 2021, 9:35:59 PMAug 9
to LAStools - efficient tools for LiDAR processing
I have some data that I was told was horizontally in MS state plane east USFt but the elevation are WGS84 Ellipsoidal height.....
Need those elevations as ground through geoid 18. I'm not sure of the exact command to just change the elevations? I'm not for sure but is not already in at orthometric height? I'm I missing something in the lasinfo report?

Here is the info on the sample of data I recieved.................

lasinfo (210628) report for 'bsb test_dsm_100cm.las'
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:        1.2
  system identifier:          'libLAS'
  generating software:        'libLAS 1.8.1'
  file creation day/year:     203/2021
  header size:                227
  offset to point data:       1561
  number var. length records: 4
  point data format:          3
  point data record length:   34
  number of point records:    129544
  number of points by return: 0 0 0 0 0
  scale factor x y z:         0.001 0.001 0.001
  offset x y z:               970000 324000 0
  min x y z:                  968452.838 324326.333 -102.584
  max x y z:                  973173.953 324949.691 -76.917
variable length header record 1 of 4:
  reserved             43707
  user ID              'LASF_Projection'
  record ID            34735
  length after header  160
  description          'GeoTIFF GeoKeyDirectoryTag'
    GeoKeyDirectoryTag version 1.1.0 number of keys 19
      key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
      key 1025 tiff_tag_location 0 count 1 value_offset 1 - GTRasterTypeGeoKey: RasterPixelIsArea
      key 1026 tiff_tag_location 34737 count 65 value_offset 0 - GTCitationGeoKey: NAD_1983_StatePlane_Mississippi_East_FIPS_2301_Feet (deprecated)
      key 2048 tiff_tag_location 0 count 1 value_offset 4269 - GeographicTypeGeoKey: GCS_NAD83
      key 2049 tiff_tag_location 34737 count 6 value_offset 65 - GeogCitationGeoKey: NAD83
      key 2054 tiff_tag_location 0 count 1 value_offset 9102 - GeogAngularUnitsGeoKey: Angular_Degree
      key 2057 tiff_tag_location 34736 count 1 value_offset 6 - GeogSemiMajorAxisGeoKey: 6378137
      key 2059 tiff_tag_location 34736 count 1 value_offset 5 - GeogInvFlatteningGeoKey: 298.2572221
      key 2062 tiff_tag_location 34736 count 7 value_offset 7 - GeogTOWGS84GeoKey: TOWGS84[0.9956,-1.9013,-0.5215,-0.025915,-0.009426,-0.011599,0.00062]
      key 3059 tiff_tag_location 0 count 1 value_offset 1 - key ID 3059 not implemented
      key 3072 tiff_tag_location 0 count 1 value_offset 32767 - ProjectedCSTypeGeoKey: user-defined
      key 3074 tiff_tag_location 0 count 1 value_offset 32767 - ProjectionGeoKey: user-defined
      key 3075 tiff_tag_location 0 count 1 value_offset 1 - ProjCoordTransGeoKey: CT_TransverseMercator
      key 3076 tiff_tag_location 0 count 1 value_offset 9003 - ProjLinearUnitsGeoKey: Linear_Foot_US_Survey
      key 3080 tiff_tag_location 34736 count 1 value_offset 1 - ProjNatOriginLongGeoKey: -88.83333333
      key 3081 tiff_tag_location 34736 count 1 value_offset 0 - ProjNatOriginLatGeoKey: 29.5
      key 3082 tiff_tag_location 34736 count 1 value_offset 3 - ProjFalseEastingGeoKey: 984250
      key 3083 tiff_tag_location 34736 count 1 value_offset 4 - ProjFalseNorthingGeoKey: 0
      key 3092 tiff_tag_location 34736 count 1 value_offset 2 - ProjScaleAtNatOriginGeoKey: 0.99995
variable length header record 2 of 4:
  reserved             43707
  user ID              'LASF_Projection'
  record ID            34736
  length after header  112
  description          'GeoTIFF GeoDoubleParamsTag'
    GeoDoubleParamsTag (number of doubles 14)
      29.5 -88.8333 0.99995 984250 0 298.257 6.37814e+006 0.9956 -1.9013 -0.5215 -0.025915 -0.009426 -0.011599 0.00062 
variable length header record 3 of 4:
  reserved             43707
  user ID              'LASF_Projection'
  record ID            34737
  length after header  72
  description          'GeoTIFF GeoAsciiParamsTag'
    GeoAsciiParamsTag (number of characters 72)
      NAD_1983_StatePlane_Mississippi_East_FIPS_2301_Feet (deprecated)|NAD83| 
variable length header record 4 of 4:
  reserved             43707
  user ID              'liblas'
  record ID            2112
  length after header  774
  description          'OGR variant of OpenGIS WKT SRS'
reporting minimum and maximum for all LAS point record entries ...
  X            -1547162    3173953
  Y              326333     949691
  Z             -102584     -76917
  intensity           0          0
  return_number       0          0
  number_of_returns   0          0
  edge_of_flight_line 0          0
  scan_direction_flag 0          0
  classification      0          0
  scan_angle_rank     0          0
  user_data           0          0
  point_source_ID     0          0
  gps_time 0.000000 0.000000
  Color R 0 65280
        G 0 65280
        B 0 65280
number of first returns:        129544
number of intermediate returns: 0
number of last returns:         129544
number of single returns:       129544
WARNING: there are 129544 points with return number 0
WARNING: there are 129544 points with a number of returns of given pulse of 0
histogram of classification of points:
          129544  never classified (0)

George S. Mercier

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Aug 10, 2021, 12:13:26 PMAug 10
to LAStools - efficient tools for LiDAR processing
Obviously the elevations are not ground but I'm not sure how to read that out of the header info........
Sample data can be found here....   DATA

Martin Isenburg

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Aug 10, 2021, 3:59:27 PMAug 10
to LAStools - efficient command line tools for LIDAR processing
There are two tools in LAStools that can go from ellipsoidal to orthometric elevations: lasheight and lasvdatum

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