| The 
are | 
1 map 
| Photo Flight ) d 
; i it do: 
horizontal height 
evaluation determination 22. 
Aero 
VTT : : subs 
HE Triangulation prog 
(Image ) Matching DTM Univ 
T Matching Relief Model (DEM) Pain 
a 
Digitization of all building Soo" 
polygones using Arcview 2.3. ! 
1 Scar 
Merging polygones and DEM / DTM E 
including calculation of statistics for every building size 
prodi 
Y scan 
remeasurement Stereo - editing 
polygones building heights 3. 
| 
= te) : E 3 m 
Automatic integration of the remeasurement din 
Output prodi 
: = = raste 
Vectormodel including attributes Ks . 
Rastermodel DEM (1m, 5m) á ort 
eo 
DTM (1m, 5m) It sh 
building model including attributes RC 
‘ Vegetation hard 
mn mode 
Fig 2: Sequence of building model acquisition Data 
done 
morpl 
2.1. Aerial photography gradi: 
despi 
The prerequisite for successful evaluation is aerial Flight Parameters 
photography which fulfils the following criteria: Pi . 34. C 
« Care should be taken in preparing the flight path so IE mates Colour 
ve P focal length 30 cm 
that systematic positional and relief errors are avoided by b 12:500 The « 
flying perimeter strips vertical to the area of interest. Scale number 7 87 gener 
- A focal length of 30 cm should be used in urban | GTOund cover 875 m buildi 
areas in order not to have to take account of more areas Flight altitude 3,750 m ; repre: 
of potential blind spots in the stereo model overlap approx 65% The g 
than necessary and in order to minimize radial distortion sidelap approx 30% 35 cm 
at the edges of the ortho photos. Base length 1000 m oh 
- Aerial photography in spring or autumn, i.e. outside Gap between flight paths 2000 m 3.2. N 
the vegetation periods, simplifies the automatic height Tab. 1: Flight Parameters 
finding of buildings and the earth's surface. Mosa 
The further details assume standard aerial photography compl 
with the following parameters: edges 
aerial 
pixel r 
318 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996