[Liblas-devel] Re: GetProj4() string and NAD83

[Martin Isenburg]

Hi,

when debugging GDAL it may help to look at what LASlib's
geoprojectionconverter does, which finds that the file
"IowaDNR-CloudPeakSoft-1.0-UTM15N.las" has correct GeoTIFFs . When I
create an intensity grid with

lasgrid -i IowaDNR-CloudPeakSoft-1.0-UTM15N.las -intensity -opng -step 3

the generated intensity raster is automatically geo-referenced and a
corresponding KML file is generated that places the PNG onto Google
Earth at the exact right spot as you can see here:

http://lastools.org/download/data/IowaDNR-CloudPeakSoft-1.0-UTM15N.kmz

Cheers,

Martin @lastools

PS: below is the report of lasinfo -i IowaDNR-CloudPeakSoft-1.0-UTM15N.las

reporting all LAS header entries:
  file signature:            'LASF'
  file source ID:            0
  global_encoding:           0
  project ID GUID data 1-4:  0 0 0 ''
  version major.minor:       1.0
  system identifier:         ''
  generating software:       'CPS/RTW LAS Lib v1.08'
  file creation day/year:    0/0
  header size                227
  offset to point data       639
  number var. length records 3
  point data format          1
  point data record length   28
  number of point records    5847380
  number of points by return 2920986 2926394 0 0 0
  scale factor x y z         0.001 0.001 0.001
  offset x y z               0 4000000 0
  min x y z                  614000.000 4791999.999 311.676
  max x y z                  615999.990 4793999.989 398.959
variable length header record 1 of 3:
  reserved             43707
  user ID              'LASF_Projection'
  record ID            34735
  length after header  88
  description          'Projection Info'
    GeoKeyDirectoryTag version 1.1.0 number of keys 10
      key 1024 tiff_tag_location 0 count 1 value_offset 1 -
GTModelTypeGeoKey: ModelTypeProjected
      key 1026 tiff_tag_location 34737 count 13 value_offset 0 -
GTCitationGeoKey: UTM zone 15N
      key 2050 tiff_tag_location 0 count 1 value_offset 6269 -
GeogGeodeticDatumGeoKey: Datum_North_American_Datum_1983
      key 2056 tiff_tag_location 0 count 1 value_offset 7019 -
GeogEllipsoidGeoKey: Ellipse_GRS_1980
      key 3072 tiff_tag_location 0 count 1 value_offset 26915 -
ProjectedCSTypeGeoKey: PCS_NAD83_UTM_zone_15N
      key 3075 tiff_tag_location 0 count 1 value_offset 1 -
ProjCoordTransGeoKey: CT_TransverseMercator
      key 3076 tiff_tag_location 0 count 1 value_offset 9001 -
ProjLinearUnitsGeoKey: Linear_Meter
      key 4096 tiff_tag_location 0 count 1 value_offset 5103 -
VerticalCSTypeGeoKey: VertCS_North_American_Vertical_Datum_1988
      key 4097 tiff_tag_location 34737 count 19 value_offset 13 -
VerticalCitationGeoKey: GEOID 2003 Applied
      key 4099 tiff_tag_location 0 count 1 value_offset 9001 -
VerticalUnitsGeoKey: Linear_Meter
variable length header record 2 of 3:
  reserved             43707
  user ID              'LASF_Projection'
  record ID            34737
  length after header  32
  description          'Projection Info'
    GeoAsciiParamsTag (number of characters 32)
      UTM zone 15N GEOID 2003 Applied
variable length header record 3 of 3:
  reserved             43707
  user ID              'CloudPeakSoft'
  record ID            0
  length after header  128
  description          'CPSInfo'
the header is followed by 2 user-defined bytes
reporting minimum and maximum for all LAS point record entries ...
  x 614000000 615999990
  y 791999999 793999989
  z 311676 398959
  intensity 1 3240
  edge_of_flight_line 0 0
  scan_direction_flag 0 0
  number_of_returns_of_given_pulse 2 2
  return_number 1 2
  classification 1 12
  scan_angle_rank 0 0
  user_data 0 0
  point_source_ID 14 18
  gps_time 597987.305116 600731.680834
overview over number of returns of given pulse: 0 5847380 0 0 0 0 0
histogram of classification of points:
  2762810 Unclassified (1)
  2156929 Ground (2)
     6318 Low Point (noise) (7)
   921323 Overlap Points (12)