Performing the pit identification procedure on whole
dataset one more time, the procedure detects some
sporadic pits, mostly without significant impact on the
DEM surface. These pits are present because of
interpolation and rasterization process, and mostly have
no significant depth. The final result after interpolation
with pitpaths included as formlines is shown in picture
below.
Fig.8. The visualisation of the whole test area after pit removal process.
5. Conclusion and further perspectives:
As we have seen, the water (low analysis can
significantly improve the DEM in geomorphological
sense.
Statistical methods of preprocessing and interpolation are
well suitable to filter out the points that do not lie on the
terrain and to minimize random errors. Thus interpolated
surface will pass very closely to original terrain, but if we
expect that interpolated surface satisfies some
geomorphometric constraints, they have to be included
into interpolation. Pit processing procedure, shown
above, is only a simple way to include geomorphometric
constraints into interpolation.
The results are promising, although the pit removal
algorithm introduced here shows dificulties in areas
where pits really exist and should remain included in
DEM, too. This problem leads to be solved at the
preprocessing phase where the clasification of pits should
be done. This clasification should be performed
according to the size of a pit and to average penetrating
rate of laser beam. After clasification, the big pits should
be masked out for further processing.
Further, the drainage lines (rivers) detection, and
including it into interpolation could significantly improve
geomorphological consistency of DEM. How derived
rivers can impact interpolation of DEM will be
investigated .
The pits identification and processing algorithms are
realised by means of softvare MATRIX (developed by
Dr. Wolfgang Rieger), and will be included into SCOP-
XX framework as a module named HYDRO. At this
stage this module does some more analysis about water
summation, rivers and catchbasins identification, but is
still being developed.
