The extent of glaciers in the former territory of the Austrian Empire has reduced alarmingly since the end of the Little Ice Age in 1850 until today due to global warming. The first depiction of the glaciers extent in this area dates back to the beginning of the 19th century, when the second Austrian military topographic survey began. By the year 1915, four surveys were made. Most of these maps are available in digital georeferenced form on the Mapire web portal. In this graduation thesis, we acquired glacier areas on the former Austrian Empire territory forms of 2nd and 3rd military topographic surveys, with the tool provided by the Mapire portal. In the Google Earth Pro we acquired glacier surfaces for the same glacier, from recent satellite imagery with a known recording date (between 2012 and 2017. We analysed the reduction of the glacier areas between 2nd and 3rd military and satellite imagery. On the test cases of the glacier Lamkopf, the glacier Ahrn and the Triglav glacier we also analysed the accuracy of area acquisition. The area accuracy of the glacier Lamkopf, when using the web portal Mapire is 2 hectares, ArcMap 0.6 hectares, and 0.3 hectares in the Google Earth Pro. The total area of the glaciers in the former territory of the Austrian Empire reduced on 79 % between the time of production of the 2nd military survey maps (between 1808 and 1835) and today. Moreover, in the case of smaller glacier groups, where the glacier group today does not cover more than 5 km2, the area reduced by 87 % and in the case of bigger glacier groups by 77 %.
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