The thesis is focused on documentation and identifi cation of postmedieval field fortifications. Fortifications were searched on the sheets of 1st Military Survey. There were collected 60 objects in different state of disintegration. Several analyses in GIS were aimed to fi nd out and verify the relations of the fortifi cations to the terrain. Elevation, proximity to watercourse and roads were detected. Based on the combination of diff erent sources the fortifications were dated to the War of Bavarian heritage (1778–1779), though it might be said that their strategic positions have been used in previous conflicts as well. The paper tried to determine the possibilities of cartographic sources and how much information they provide. The final conclusion is that such sources are ideal for studying the postmedieval/modern landscape. Research of the remains of field fortifications should be done with the usage of various sources. Proper research is based on the knowledge of possible written sources followed by iconography, toponomastic, cartographic and especially archaeological sources which, used in combination, aim to the best results of the research.