International Archives of Photogrammetry and Remote Sensing, Vol. 32, Part 3W14, La Jolla, CA, 9-11 Nov. 1999 
      
Figure 5: Ground model with shading, the break lines are maintained 
different approaches for this end [Rieger et al., 1999b] 
and [Wild and Krzystek, 1996]. 
The automatic elimination of negative blunders is not opera- 
tional at the moment. In water areas it is possible to apply the 
algorithm with a weight function mirrored to the one shown 
in fig. 2. 
Another aspect we are currently working in is the derivation 
of a DTM in the city. To this end we are using a 0.5m-grid. 
Negative blunders can also be found in this data set. - 
Implementation work as well as theoretical extensions to the 
overall process of laser scanner data processing are necessary. 
The use of other data sources (e.g. aerial images) as well 
as the derivation of additional surface information from laser 
scanner data are one area of research. Though the degree of 
automation is very high, it is our aim to further increase the 
automation in laser scanner data processing for the derivation 
of high quality DT Ms. 
Acknowledgements 
This research has been supported by the Austrian Science 
Foundation (FWF) under Project No. P14083-MAT and 
No. P12812-INF. 
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