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SCOP AS AN ALL-PURPOSED TOOL FOR ELABORATION OF DIGITAL TERRAIN MODEL 
- THE USER'S COMMENTS 
Marta Borowiec, Krystian Pyka 
The Department of Photogrammetry and Remote Sensing Informatics 
St.Staszic University of Minig and Metallurgy, Krakow, Poland 
Commission IV, Working group 4 
KEY WORDS : DEM/DTM, GIS, Digitization, Orthoimage, Acqiusition, Modeling 
ABSTRACT 
Depending on the scale, scope and kind of problems solved by the spatial information system (GIS,LIS) they need to 
be supported by DTM with different degree of accuracy and minuteness of detail. 
The quality and accuracy of DTM depend on the data-acquisition and the mathematical technique of interpolation. In 
this paper, the acquirements with different projects, which purpose was a description of the surface of the earth as well 
as another objects, will be presented. These experiences were carried out in 1993-96, thanks to supplying us with the 
SCOP package within the framework of Central European Initiative (CEI). 
1. INTRODUCTION 
Since mid 1993 the Department of Photogrammetry and 
Remote Sensing Informatics at AGH has got the 
specialistic SCOP (Stuttgart COntour Programme) 
package. The package is a result of many years long 
experiments carried out by researchers at Stuttgart and 
Vienna Universities. It has been continuously modernised 
and developed. 
It is indispensable in GIS systems to have information 
about the surface relief. The most popular forms of 
representation of the terrain topography are isolines or 
regular grids. The grid form, is more applicable because 
it gives possibilities for 3-D space analyses and is 
necessary for ortho-rectification of aerial or satellite 
images. 
The source of data for DTM creation can be different, but 
most often the data are collected from topographic maps 
or aerial photographs. The choose of data source and the 
method of their digitization depends on many factors as: 
- data accessibility; 
- required accuracy; 
- time and costs of production. 
In the last 2 years the Department of Photogrammetry 
and Remote Sensing Informatics accomplished several 
projects related to creation of a DTM. In each of the 
projects the SCOP was used to create DTM 
independently from data acquirement method. 
In the paper, the authors present the way of 
such data preparation for reliable SCOP interpolation 
avoiding impact of big differences in data density. 
2. DATA ACQUISITION 
The accuracy of DTM is strongly related to the method of 
data acquisition. Direct geodetic survey is the source of 
the most accurate hights information. A competitive 
method, especially from the viewpoint of economy, is 
photogrammetric survey. 
When accuracy requirements are low then digitization of 
the existing cartographic maps is a relatively cheap and 
fast method for data acquisition. The latter method is 
661 
widely used in data collecting for Geographical 
Information Systems ( GIS). 
In our projects we have applied various methods of data 
acquisition: direct digitization of topographic maps, 
digitization of scanned maps, stereo-digitization of aerial 
photographs, and direct field measurements with use of a 
total station. The variety of these methods is presented in 
Table 1, which contain short characteristic of some 
projects. 
3. MATHEMATICAL MODEL OF INTERPOLATION 
In each projects shown in Table 1, the SCOP was used 
to create DTM. In comparison with other programs in the 
field of DTM, the SCOP has some particular features, 
among others: 
- four categories of points are taken into consideration 
in the interpolation process: dispersed points, spot 
heights, sequences of points that create the form 
lines, and break lines, 
- the possibility to assign different accuracy to data 
allows for interpolation with filtration. 
The SCOP reliably models the terrain relief in those 
cases where the data are obtained along profile lines 
supplemented with the structural lines. It is interesting 
that the SCOP program is easier to use for mountainous 
and wavy terrains than for the plane ones. In the latter 
case it requires a significantly higher density of data than 
it can be obtained from contour line digitization. 
The effects of SCOP interpolation are not stable in 
areas of different density of data. This occurs especially 
in places where the flat terrain transits into elevated 
surface. 
The linear prediction method was used to interpolate the 
DTM points. This method is reliable to cope even with the 
most complicated surfaces including the elements of 
their discontinuity. However, the calculation parameters 
should be choosen with caution and data have to be 
properly prepared. For proper interpolation program 
requires similar data density for the whole area, what in 
many cases is difficult to achieve. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996