Calibration of raster image using GIS class software- A ccuracy analysis

Most of the information related to our environment directly relates to a specific location on the surface of the Earth-spatial data. From the beginning of his existence, the man collected them and made their analysis. Over time, their number increased so that geographic information systems (GIS) were necessary for their storage and processing. The basic GIS functions include collecting, verifying, managing, processing, analyzing and visualizing data. It is the data, next to people, equipment, software and procedures that are the basic element of such systems. Despite the huge technological progress, the basic source of information for this type of systems are still scanned analogue maps. Very often they are the only available material necessary to assess the spatial changes of the environment. However, in order for the information constituting the content of the map to be able to supply the databases of geographical information systems, it is necessary to give them spatial orientation. This can be during the calibration process. The quality of the data and the level of analyzes are largely dependent on the method and error of fitting the spatial map. Significant geo-referencing possibilities are provided by the GIS class software, among others QGIS software.