DIGITAL DATA ACCURACY BY 
ANALYTICAL STEREOPLOTTER 
Sergey S.NEKHIN 
Central Research Institute 
of Geodesy, Air Survey and 
Cartography (TsNIIGAiK) 
Moscow, USSR 
Abstract 
Results of digital terrain data accuracy investigation are 
presented. The data was obtained with analytical stereoplotter 
Anagraph. Brief description of the stereoplotter as well as 
its characteristics and technological capabilities are given. 
Accuracy of data digitized from tesi area photographs by the 
analytical stereoplotter was compared for the cases when: sys- 
tematic errors of image and model were ignored, image errors 
were compensated by field and self calibration data, model er- 
rors were compensated by polynoms (multiquadrics). Geodetic 
coordinates of points as well as photogrammetric coordinates 
of points obtained from phototriangulation by bundle adjust- 
ment with self calibration were used as control. It is conclu- 
ded that analytical stereoplotter Anagraph is very efficient 
when used for digital terrain data acquisition and large-scale 
mapping. 
Raising efficiency and quality of topographic maps and 
plans production to a large extent depends upon accuracy of 
airphoto photogrammetric processing and degree of its automa- 
tization. One way of solving this task is to use analytical 
photogrammetric instruments (API) based on the employment of 
computers and automatic systems in combination with tradition 
optical mechanical devices. Analytical stereoplotter Anagraph 
developed in TsNIIGAiK is a system of such type. 
Anagraph comprises: 
1) stereocomparator with minicomputer determining the position 
of its carriages by commends translated through servosystems; 
2) automatic plotter that enables to draw or engrave map con- 
tents according to orders coming through the servodrive and 
computer from stereocomparator when operator moves the measu— 
ring mark along the stereomodel surface; 
3) minicomputer with the software complex operating the whole 
cycle of photographs processing and map and plan compilation; 
4) alphanumeric display with a keyboard that provides to maine 
tain operator's dialogue with computer and the whole system; 
5) control console allowing input of various characteristics 
wR numbers for map and plan compilation and data acqui- 
sition; 
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