2. FUNDAMENTALS OF VIRTUAL SPATIAL DATA 
PRESENTATION 
Basically in a MIS the Spatial position of MIS relevant points is 
described by its (Cartesian) coordinates. Based on these 
coordinates the traditional Geometric content of a MIS are 
- numeric coordinates of object points, printed in a list or 
stored on digital storage media and/or 
- 2 dimensional digital or analog line maps, namely based 
on vector data and/or 
- . 2 dimensional image maps, based on raster data. 
In addition to these traditional Geometric deliverables of a MIS 
the virtually 3dimensional presentation for MIS data, as a 
modern tool for improved MIS data visualization is highly 
recommended. 
To verify this, two images of the same object, gained from two 
different viewing positions with at least approximately parallel 
look directions are required. 
It shall clearly be stated, the derived stereo mates can be of real 
as well as of synthetic origin! 
The typically appearance of a stereoscopic impression, while 
viewing two corresponding stereo mates, is due to the ability of 
the human 3dimensional viewing sense. 
In principal a synthetic stereo mate will be obtained from a 
Geometric manipulation of the original image, by adding 
appropriate horizontal parallaxes values to the original 
monoscopic image. 
This way for a 3 dimensional presentation of MIS data is of 
course open for vector as well as for raster data. 
In figure 1 are presented advantages from using stereo mates for 
image data visualization. In detail, as a sample, in figure 1 there 
the interpretation results of different topographic features as 
interpreted in original images of extremely high resolution in 
comparison with digital images showing 2.5 m, 5m, 10m, 15 
m, 20m and 40 m ground Pixel size. As higher the values in the 
diagram, as higher the accuracy of interpretation. From the 
sketch in figure 1 it is a remarkable result, the stereo mates will 
highly improve the MIS data visualization in general, which is 
indicated in particular for buildings and for object features 
(DTM), see figure 1. 
Traditionally the horizontal parallaxes values are close related 
to the object space and in particular to differences in object 
heights. Apart from this, the actual meaning of the horizontal 
parallaxes may vary extremely due to different application 
aspects of the map respectively the MIS data to be spatial 
visualized. For example, the 3™ dimension in the spatial MIS 
data provided, can represent variations in temperature, in the 
restoration or production progress as well in frequency (of 
visiting) and color (relicts), etc.. 
3. METHODS FOR STEREOSCOPIC VIEWING 
OF MIS DATA 
Independent of the nature of the horizontal parallaxes, an 
attempt for a systematic investigation of the complete list of 
virtually stereo aids according to the state of the art, has been 
carried out. 
The principles of the 3dimensional viewing technology have 
been categorized according to 
* methods for the spatial presentation of stereo mates projected 
without contact, 
* methods for the separation of spatial presented stereo mates 
projected in contact and 
* methods using virtually 3 D models 
Sticking to appropriate virtually stereo data representation, no 
part of this investigations are, e.g., methods using simple central 
perspective effects and/or shadow effects, "2.5 D effects" by 
permanent moving of a queue of central perspective images or 
"continuous profiling", which are methods for 3D data 
determination by combining a successive queue of profiles, but 
not own methods for virtually 3D data presentation, similar 
holds for the Moiré effect, while materialized 3D appearance, 
including the 3D mirror effect and real models are no methods 
for virtually but for real 3dimensional presentation. 
Mapping potential of rasterimagery and photos 
{for medium scale topographic mapping of rural areas) 
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Figure 1. Results of advantages from Spatial image data interpretation 
—550— 
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