while reading and writing raster data. This is very
important because it dramatically shortens the time
of rectification. PhoTopoL also uses special caching
system for reading and writing data, which enables to
have in memory only that part of raster which is to
be used.
Existing DEM for the Nymburk region was used as a
next data source for the rectification. DEM developed
in military topographic center, which is available for
the whole Czech Republic, was utilized. This DEM is
a grid model and the size of grid is 100 m. While im-
porting into PhoTopoL the model was resampled with
bipolar interpolation of elevation values into new grid
size of 20 m.
The world coordinates of control points were collected
before calculation of absolute orientation. These
points were stored within TopoL GIS vector data
block (layer). They were picked up from the maps
in the scale 1 : 5,000.
The whole region was divided into several subre-
gions. These ones were designed to fit the map sheets
with small overlay. First of all, the absolute orien-
tation of all photographs in the subregion were cal-
culated. Then the orthophoto rectifications in Pho-
TopoL's batch mode were run. After that the mosaic
of the whole subregion was created from the rectified
photographs. The resulting mosaic was cut into final
map sheets.
This project was performed in March 1996. After all
we are able to say that all process including scanning,
image and DEM import, collection of control points,
rectification, mosaicking and cutting into map sheets
took about 10 days for two persons. PhoTopoL was
run on PC computers equipped with Pentium 90 MHz
processors, 16 MB RAM, 1 GB disk. Optical storage
device was attached to one of these PCs and comput-
ers were connected within computer network.
5 Conclusion
This paper demonstrate that PhoTopoL can meet
many needs for digital photogrammetry, image-
304
analysis, remote-sensing, and GIS software in one
package. It offers end to end solution for the map pro-
duction as well as image analyses. Decreased price of
both hardware and software solution lets to have more
these low-cost personal systems and work very effec-
tively and quickly, which means higher productivity
for digital photogrammetry. Standard personal com-
puters and environment protect hardware and soft-
ware expenses and increase their effectiveness.
The inclusion of TopoL GIS in the PhoTopoL sys-
tem offers large base for direct use of photogrammetric
data and results in other geodata analyses. This paper
presented the use of PhoTopoL in real practice. We
described middle-scale project in detail as well as var-
ious applications (forestry, aerial photoplans, regional
management) in brief overview.
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[1] Ebner, H., Fritsch, D., Heipke, C. (eds.) 1991.
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Fórstner W., Ruwiedel, St. (eds.) 1992. Robust
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Fritsch, D., Hobbie, D. (eds.) 1995. Photogram-
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Nwosu, Z.A.: Digital Versus Analytical: A Mat-
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Pivnicka, F. 1996. PhoTopoL - User’s Guide. Help
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996
