AERIAL TOPOGRAPHIC SURVEY OF SMALL AREAS BY "LOW-COST" DIGITAL CAMERA CANON EOS 5D

Spatial data acquisition about the features on the georelief and terrain introduces high time and costs phase of the thematic mapping projects processing. Comparing to the classic geodetic survey methods (used in land survey), those photogrammetric have main advantages, such as high temporal resolution, full textural information about the observed area and moreover to bring cost benefits regarding to field work. Modern technologies developed for the professional photography devices are step by step being released to the market with commercial professional, semi-professional and compact cameras that are sold with considerably lower prices. On the other hand a rapid increase of the overall image quality acquired with these cameras provides possibilities for their usage in photogrammetric tasks. Nowadays very common UAV (Unmaned Aerial Vehicles) technologies bring many limitation problems caused by law, which make flying over built-up areas impossible, need of visual contact with UAV, range of control radio, limited possibilities of technical conditions according to energetic availability of UAV etc. Solution of this problem is to install semi-professional or compact camera to ultra light airplane controlled by man. Paper stresses about possibility to collect spatial data by aerial topographic surveying. Mathematical and statistical models have been used for photogrammetric survey of images acquired by non-metric camera CANON EOS 5D. Processed images have been acquired on the 500 and 900 m flying altitude. Spatial accuracy has been estimated on the clearly identified points of interest and height accuracy of terrain surface. The final quality of spatial positioning depends on geometry of aerial imaging, camera stability and elements of interior orientation estimation by camera calibration. Light conditions and texture of surveying area have been taken into consideration as well. On the basis of the gained results of accuracy m(YX) = 0,17 m, m(H) = 0,27 m and extent of area of interest, possible domains of exploitation of such a data exploitation have been defined. Another positive factor is a ratio between gained accuracy and time/cost demand on the spatial data acquisition compared with other methods.