The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008
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Figure 1. Stereo IKONOS imagery covering the related region.
The terrain is partly rough and the elevations in the region
change between 1000 m. and 1500 m. In this region, there are
Selcuk University Campus and small urban areas. The other
parts of the terrain contain open fields without any trees. There
are no high trees or plant cover. Rational Polynomial
Coefficients (RPC) files are provided with the imagery. The
RPC file provide camera model data for 3D photogrammetric
compilation, for production of digital elevation model and
orthorectification. The stereo reference images are the least
processed images.
2.2. Field Studies and Measurements
2.2.1. Spatial data-acquisition with the conventional method
The main principle of “the conventional method” also named as
“the polar method” is the determination of the horizontal and
vertical position data of the detail points simultaneously by the
help of the horizontal angle (P), vertical angle (Z) and the
horizontal distance (S) observed at the detail points with an
electronic tachymeter installed on the definite control points in
which coordinates are known. The observations made with the
electronic tachymeters are automatically recorded to the
recording units and transferred to the computer environment in
order to make calculations and drawings. In the conventional
method, TOPCON GTS-701 electronic tachometry with ± 2”
angle measuring accuracy and ±2 mm + 2ppm.D length
measuring accuracy (m s ) was used. Evaluating the
measurements obtained by the field studies with a CAD based
professional computer program (NETCAD) after transferring
them into the computer medium, the spatial data of the detail
points were obtained and the related drawings were performed
(Figure 2).
2.2.2. Ground Control Points (GCPs) and Surveying
Acquisition of ground control points (GCPs) is particularly
important for geometric correction of high resolution satellite
images. GCPs are measured with a static GPS receiver (Leica
SR 9500 dual frequency) for 30 minutes measurement and
postprocessed with a stable GPS point of Turkish National GPS
Network (for mono IKONOS imagery 8 GSPs , Stereo
IKONOS Imagery 26 GCPs). The accuracy of the measured
GCPs is thought to be lower than 0.1m. The processing and
adjustment of the GPS observations were made using the SKI
Pro software of Leica. The points are marked on the ground as
three lines containing one dot in the centre (Figure 3). The
marking accuracy of the GCPs is assumed to be 0.5-1.0 m. The
distribution of the points is seen in ( Figure 4).
