created with command line: spfinalize -i TO_core_last.las -ospb | \ spdelaunay2d -ispb -osmb | \ tin2iso -ismb -range 40 400 10 -oslb | \ slclean -islb -oslb -length 5 | \ slsimp -islb -oslb -area 1 | \ sl2sl -islb -okml -tiling_nlls c:\kml_files\toronto 629500 4834000 500 -utm 17S -ellipsoid 23 -elev_offset 42 data available here: http://www.geoict.net/LidarData/Data/OptechSampleLAS.zip download executables and sources here: http://www.cs.unc.edu/~isenburg/googleearth/ question: i am a complete novice in terms of datums and ellispoids. in the meta data of this data set from toronto downtown it reads: "[..] contains coordinates in WGS84 UTM North with elevation in height above the ellipsoid and intensity of the each return. All data is in UTM zone 17. The sample data set contains only last pulse laser returns. Laser points are listed in order of acquisition and will load into visualization software as six NE-SW oriented strips." if i run my lasinfo.exe too on the LAS LIDAR points (see output below) i see that all the elevation values are between 40 and 398 meters. but if i check google earth then the elevation starts at 269 feet in this area of toronto downtown ... hence ... i have to add about 42 meters "by hand" to make the contour lines in this google earth show up at the right elevation. but ... google earth states it also uses the WGS84 ellipsoid. any idea where the difference could come from? --- C:\lastools\lasinfo C:\data\OptechSampleLAS\TO_core_last.las reporting all LAS header entries: file signature: 'LASF' file source ID: 0 reserved: 0 project ID GUID data 1-4: 0 0 0 '' version major.minor: 1.0 system_identifier: '' generating_software: 'TerraScan' file creation day/year: 0/0 header size 227 offset to point data 229 number var. length records 0 point data format 1 point data record length 28 number of point records 3200079 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 629881.47 4834014.94 40.88 max x y z 631100.51 4835369.73 398.51 reporting minimum and maximum for all 3200079 LAS point record entries ... x 62988147 63110051 y 483401494 483536973 z 4088 39851 intensity 10 51000 edge_of_flight_line 0 0 scan_direction_flag 0 0 number_of_returns_of_given_pulse 1 2 return_number 1 2 classification 1 1 scan_angle_rank 0 0 user_data 1 6 point_source_ID 0 0 gps_time 412789.182400 414864.349600 actual number of points by return is different: 1886989 1313090 0 0 0 overview over number of returns of given pulse: 1886989 1313090 0 0 0 0 0 histogram of classification of points: 3200079 Unclassified (1)