The design work on the objects of large area need to know not only surface of object in horizontal projection but also spatial (real) dimensions of the surface. The rapid development of digital terrain models can improve the site of such works. It was developed a number of computer programs to calculate the real (spatial) surface area based on set of DTM held. The possibility of using by the users (designers) the existing and newly created DTM obtained by different methods, will depend primarily on the accuracy of these models. The study subjects were taken effect accuracy of the DTM on the accuracy of calculating the surface area approximated. The conducted analysis can be helpful to users in selecting the optimum data of DTM for the specific purposes, from set of data collected in the state geodetic resources.

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