International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
eliminates geometric and topologic errors exactly, at the same
time of object digitizing and drawing. IPCBS is the software
which can be accommodated by any existing hardware, software
and standards and also from financial point of view is truly
economic. In this system, photogrammetric tools of an
analytical plotter (i.e. PlaniComp P33) are embedded within
CAD program (ie. MicroStation), and in addition some
modification can be performed on objects (i.e. data cleanup)
and some definitions (i.e. some of topology relationships) can
be assigned to objects before inputting data to CAD kernel.
Outputs of this system can be entered to GIS systems or
automatic cartography systems without need for further editing
process. This software can be accommodated by existing
hardware, software and standards and from financial point of
view is economic. These techniques were tested using simulated
and real data. Output file of this program tested in several GIS
softwares (i.e. Arclnfo 8.0, ArcView 3.1). The results were
completely satisfactory.
Following geometric errors can be removed by IPCBS program:
— Removing overshoots and undershoots;
— Nodes editing (clustered nodes or mismatches at
nodes);
— Dissolving duplicates/overlaps;
— Removing virtual sliver polygons;
— Edge matching error;
— ]ntersection processing (crossing objects error and
polygon closure error and dangle error);
Geometric data will also be optimized in the following ways:
— Thinning (line-weeding);
— A Removing small elements.
5.2 Recommendations
Since, post-processing step for data editing will be omitted by
using integrated systems, so we propose use of integrated
systems in all the photogrammetric projects to collect accurate
geometric data, without any topological and cleanup errors, in
order to import data directly and real-time to CAD software or
GIS environments. The future exploration would improve the
performance of the cleanup techniques already discussed in
previous chapters. Future studies should propose real-time
solution for following tasks in IPCBS cleanup module:
— Converting features with complex geometry to simple
one (stroking or simplifying features with complex
geometry like B-Splines);
— Best fitting curves (replacing broken polylines with
smooth one);
— Squaring angles near quadrant angles;
— Editing of hydrographical features (editing streamlines
and ridgelines according to contour line);
— Contour-line editing;
— Height-point editing;
— Alignment editing (e.g. building features alignment
error);
— Special functions for finding missed features at the
time of digitizing (stroke);
— Some modules for classifying feature attributes (i.e.
layer, color, style) at the time of digitizing;
— Defining priority for features according to predefined
instructions and importance of features. Because some
kind of features should be allowed to extend or snap
more and some should be less.
Using knowledge-based techniques in integration of CAD and
photogrammetry systems is the next target. Knowledge-based
techniques provide constraint-based modelling in CAD
environment and accurate measurements in digital
photogrammetric workstations [El-Hakim & Westmore, 1992].
REFERENCES
Carl Zeiss Division of Photogrammetry, 1993. P33 PlaniComp
P-Series Analytical WorkStation Operating Instructions 51-
1233e, Germany.
Carl Zeiss Division of Photogrammetry, 1994. P-CAP PC-
Sofiware for Orientation and Numeric Acquisition with the
Planicomp Operating Manual 51-1220 e, Germany.
Chapman, D., Deacon, A., Hamid, A., Kotowski, R., 1992.
CAD modelling of radioactive plant: the role of digital
photogrammetry in hazardous nuclear environments, IAPRS,
Washington, USA, Vol. 29, Part BS, pp. 741-753.
El-Hakim. S.F., Westmore. D.B., 1992, A knowledge-based
edge / object measurement technique, 1APRS, Washington,
USA. Vol. 29, Part B5, pp. 514-521.
Molkaraei, A., 1999. Instructions for Second Step of
Organization and Establishment of Database of Tehran Maps.
How to Do Manual, Tehran GIS Center, Tehran, Iran.
Neto F.A., 2001. *Data Editing".
http://www.csupomona.edu/-faneto/ce484/notes/unit03.pdf
(accessed 12 Feb. 2002)
ACKNOWLEDGEMENTS
I wish to thank Geodesy and Geomatics Engineering
Department of Khaje-Nasir-Toosi Technical University.
Special thanks go to Dr. Ebadi, Mr. MolkAraei and my best
colleagues Mr. Saraei and Mr. Rahimi for their technical
assistance.
396
? Cen
KEY W
ABSTR
Various
data hay
optimiz
water al
(especia
classes
differen
analysis
area of
separate
The go:
enhance
not only
of diffe
(b) cont
optimur
compar
beach a
results.
Image «
sensing
visual
contrast
(sce, fo
Image €
for autc
interest
environ
enhance
process
This pa
for the
differen
and mu
band c
operatic
equaliz:
enhance
whole
features
* Cort
