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

[Howard Butler]

and LAStools now does vertical datum transformations too? If so, even more reason to not use libLAS :)

On Jan 10, 2012, at 12:10 PM, Martin Isenburg wrote:

> 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)