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$3000). The first results confirm the accuracy of 50 
microns claimed by the manufacturer. It is expected 
that the deformations will show a systematic nature, 
as in the previous case. To check this circumstance 
implies using some device to move softly and 
accurately the cursor because the discrepancies are 
so small that they will not be clearly detected by free 
hand movement. Tests will continue with this tablet. 
Our interest is to check if accuracies of 25 um can be 
reached after removing systematic deformations. If 
that were the case, accuracies compatible with that of 
old second order plotters could be obtained. 
4.CONCLUSIONS 
As a conclusion, it can be said that the proposed 
plotting systems can be not only economic but can 
reach also an interesting accuracy. And all that can be 
achieved working with an image of excellent quality 
such as that provided by a mirror stereoscope, in the 
case of stereoscopic procedures, and with the 
possibility of obtaining a final product, whose richness 
and completeness are guaranteed by the use of a very 
powerful software like AUTOCAD or any other CAD 
system of similar type that could be used. 
It must be also born in mind that the described 
procedures can find application not only in mapping, 
map revision and GIS updating, but they can also be 
397 
very useful to make a first map for planning purposes 
in many regions of developoing countries lacking 
adequate cartography. In these regions, making 
preliminary sketches for planning of roads, water 
supply or irrigation, for instance, can be a huge 
problem, because maps at scales 1: 50 000, or even 
1:100 000, are simply non existent. 
REFERENCES 
LUHMANN, T., 1991. Aufnahmesysteme für 
Nahbereichsphotogrammetrie. Zeitschrift far 
Photogrammetrie und Fernerkundung, 3/91 : 80-87. 
NEWTON, |., LEATHERDALE, J. D., MULLER J. P., 
SOWTON, M. and WALKER A. S., 1991. The new 
decade : Digits and Diversity. Photogrammetric 
Record, Vol. XIII, No. 78 : 877-888. 
PETRIE, G., 1992. Trends in analytical 
Instrumentation. ITC Journal 1992 - 4 : 359-383. 
WARNER, W. S. and CARSON, W. W., 1991. Errors 
associated with a standard digitizing tablet. ITC 
Journal 1991 - 2 : 82-85. 
WARNER, W. S. and CARSON, W. W., 1992. 
Mapping monoscopically : an innovative system for 
vertical and oblique aerial photographs. ITC journal 
1992 - 2 : 228-233 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996