The process of map calibration and its impact on the quality and accuracy of cartographic materials

The calibration process is a procedure that enables adjusting the scanned portion of the map to the current frame of reference, and equipping it with cartometric properties. As a result of the said process, the raster image becomes cartographic material that can be applied, among others, to the context of geodetic work. There are numerous methods of image transformation and ways of selecting the control points, according to which this process can be carried out. In the paper, the authors present the literature review featuring various problems related to the map calibration process, as well as the methods of transformation, and the ways of selecting the control points. The work was carried out in reference to the example of scanned fragments of cadastral maps, which were then subjected to calibration processes using crosses of map graticule lines and based on situational details. The calibration process was carried out several times using a different number of adaptation points while changing their location and the manner of selection.