Reconstruction of trench line from Second World War (OKH Stellung b1) in Jałowiec range and Mędralowa mountain group by interpretation of LiDAR data model and field research

Abstract

LiDAR (Light Detection And Ranging) data are very useful in geographical, historical and archeological studies. It is because of large ALS point cloud precision, which makes possibility of studying small forms in relief, such as unmetalled roads, historical agricultural systems, archaeological sites or old field fortifications, like trench lines. The aim of this article is test on the usability of LiDAR data in research of trench lines built during Second World War in Poland, in Beskidy Mountains. The study area chosen to this text was located in Jałowiec Range and Mędralowa Mountain Group in south-west of Małopolskie voivodeship, south of Poland (Fig. 1). Jałowiec Range and Mędralowa Mountain Group is a continuation to the north of the Massif Babia Góra (Beskid Żywiecki, Carpathians). The fortifications were been built in this area before and during the Second World War. The first objects were built by Polish Army in 1939 and second time there was built two large fortification lines 1944, by polish people forced to do it by german soldiers. The most objects in studied area were made on the slopes of Malikowski Groń. Objects founded in 1944 were preserved in good condition up to the present day (Tab. 1). The few objects have been transformed by the geomorphological processes and by overgrown trees and shrubs on them. These objects have survived to this day, because they were not damaged during hostilities. The research was performed on a piece of trench line on Malikowski Groń (760 ma.s.l.) about 12,2 km long (Fig. 3, Fig. 6), Lachów Groń (708 m a.s.l.) about 1,6 km long (Fig. 3) and Mędralowa Mountain Group (1169 m a.s.l) about 2,3 km long (Fig. 4). During the field test the plan of trench lines (Fig. 3C, 5B) was performed by using GPS mapping and by measurement of the size and depth of the trenches. Second plan (Fig. 3B, 5A) is the result of LiDAR data analyses and vectorization. After then the obtained results were compared in research analysis. The trench lines and objects are quite good visible in LiDAR data, but it is impossible to do the classification of point objects made in field observation (Tab. 1, 2, 3). However, as a general comment, it is the possibility to signing the object classes in neighbor areas by way of analogy to field testing research.