Resumen
Map mosaics of the First Military Survey showing Lower Austria and Hungary (two separate zones and coordinate systems of 1:28,800 survey sections) were georeferenced. Compared to the previous fitting carried out in the framework of the publicly available MAPIRE project, an attempt was made here to determine the true native projections, despite the assumption, according to the literature, that these map works have no real geodetic basis and no real cartographic projection. In the case of Lower Austria, the native coordinate system of the Brno?Wien?Vara?din degree measurement of Father Joseph Liesganig, the Cassini projection centred on Stephansdom in Vienna, proved to be the survey?s own projection. In Hungary, in addition to the centre of a similar degree measurement, a fundamental point of the also documented Budapest-surrounding network of Colonel Neu proved to be a possible starting point of the Cassini projection used. Thus, with these centres, the Cassini projection is a good mathematical model for the native coordinate system of the surveys in these provinces. This achievement opens the possibility of better georeferencing of old maps of the survey, providing a database of land use and environmental change analyses and a step forward in understanding the survey technology of the 18th century.