The presented measurement system bases on modified videotheodolites developed within the last few years on the Institute of Geodesy and Geophysics, Vienna University of Technology (Austria). The fundamental idea of this system is to use the texture on the surface of the object to find "interesting points" by special image processing methods which can replace artificial targets. The disadvantage of such an on-line measurement system is the requirement for a well-trained "measurement expert" who has to have certain skills and experience to properly handle the complex system. To eliminate this disadvantage we implement a suitable decision system, which supports the operator. All decisions are done on the basis of appropriate values which represent the captured image and by means of a knowledge-based decision support system.