Airborne data sets on MARV4/2 --- LIDAR

LiDAR 2004 - SPARSE
  • August 5, 2004  - flight documentation
  • 900 m AGL
  • Point density 0.7 - 2 points per m2 for areas under 1, 2 or 3 strips
  • 1 or 2 returns/echoes per pulse. Minimum range-difference of 4 m
  • 506 MBytes
This data set was processed into a DTM with 1-meter resolution. The accuracy of this DTM has been evaluated to be 0.3 m or better.

Coverage of 2004 LiDAR The 2004 LiDAR flight was carried out from an airplane travelling at the speed of 75 m/s. The scanner produced a zig-zag pattern of pulses. The scanning angle was ± 20º - from an elevation of 900 m, each 6-km long strip covered a 600-m wide path. Two shorter perpendicular strips were flown - this was needed for establishing the orientation of the data - to remove possible systematic offsets in the orientation of the longer parallel strips.



The figure below gives a sample of the 2004 LiDAR points superimposed in an image pair. The HSV-coloring is scaled from 0 to 20 meters above ground i.e. the terrain elevation has been checked for each point from the DTM before the HSV-color has been determined. The images are 17 x 17 m and the area is under two parallel strips.


Sample of 2004 sparse LiDAR  
LiDAR 2006 - SEMI-DENSE

  • July 25, 2006  - flight documentation
  • 800 m AGL
  • Point density 6-9 pulses per m2
  • 1, 2, 3 or 4 returns per pulse. Minimum range-difference of 3 m
  • 18.2 GBytes

Coverage of 2006 LiDAR The 2006 data set was collected from an airplane travelling at 75 m/s. In order to get a semi-dense pattern of 6-9 points per m2, the strips have  55% overlap. The instrument could record up to 4 echoes from a pulse. The data is in so-called comprehensive format, which means that for each pulse we know the LiDAR-position, attitude in Euler angles, time, scan angle, and the positions and intensities of the four echoes. This yields 207 bytes per pulse. There can be upto 20 MBytes of data per hectare. The data is stored in binary files, one file for each KKJ-hectare.

Sample of the semi-dense 2006 data is given below.



Sample of 2006 LiDAR