130 
The special geometric conditions of SPOT images have been determined with the 
program BLASPO of the program system BLUH (Jacobsen 1988 c) which is 
respecting the orbit of the satellite. 
Several data sets have been handled, typical results are shown in table 4. The 
results achieved with Landsat TM have been published by (Ehlers 1988). 
sensor 
area 
image scale 
base/height 
Sx Sy 
[ml 
Sz 
(ml 
MC 
N. Germany 
1 
820 000 
1 
3.3 
7.7 
20.2 
LFC 
Alps 
1 
770 000 
1 
1.6 
5.8 
8.6 
KATE 
Munich 
1 
1400000 
1 
2.8 
27.2 
47.7 
TM 
Georgia 
1 
1200000 
1 
5.5 
22.0 
42.0 
KFA 
Hannover 
1 
275 000 
1 
8.3 
6.9 
36.2 
SPOT 
Marseille 
1 
400 000 
1 
1.0 
12.4 
6.5 
SPOT 
Hannover 
1 
400 000 
1 
2.9 
5.0 
19.1 
table 4: accuracies of independent check points determined by bundle adjustment 
The results listed in table 4 are typical for the sensors. In other areas similar 
results have been achieved. The horizontal accuracy is mainly depending upon the 
quality of the used control points and the point identification. The standard deviation 
Sx, Sy in the case of the SPOT-model in Marseille is limited by the poor control 
points digitized from maps 1 : 25 000. The unaccurate results of the KATE 200 
and Landsat TM are caused by the problems of point identification. The resolution is 
limited, so only intersections of highways and edges of forests could be used. With 
the exception of the KATE and TM the horizontal accuracy is sufficiant for mapping 
1 : 50 000. 
The vertical accuracy is mainly determined by the base to height ratio. So the 
optimal results have been achieved with the SPOT in the case of a base to height 
ratio of 1:1 (inclination +/- 27°) and LFC. But the listed values are only valid for 
control points which are selected in areas with higher contrast. 
In an area close to Hannover grid measurements have been made with images from 
the KFA 1000, panchromatic SPOT, multispectral SPOT and as reference with high 
altitude photos. 
sensor 
number of points 
Sz 
morefold 
Sz against RMK 
base/height 
RMK 
961 
+/- 
0.9 m 
_ 
1 : 0.6 
KFA 1000 
961 
+/- 
16.3 m 
15.1 m 
1 : 8.3 
SPOT pan 
368 
+/- 
8.6 m 
21.9 m 
1 : 2.9 
SPOT multisp. 
961 
+/- 
8.4 m 
35.5 m 
1 : 3.4 
table 5: accuracy of height measurements 
(RMK = aerial camera f=8.5 cm, flying height = 10 500 m)