This image illustrates one of the unique capabilities of laser
altimeters: to measure the canopy height of vegetation and to
simultaneously measure ground beneath vegetation. The canopy height
is colored green and transparently superimposed onto the terrain elevation image in beige.
Depending on the canopy density (type of trees, season) the density
of samples on the ground will not be as high as in open terrain.
It is, however, sufficient to generate digital (subcanopy) terrain
models (DTM) with planimetric resolutions in the order of 3-7
m and with an absolute vertical accuracy of down to 0.5 m |