The technology of digital terrain model creation on the example of defensive structures "Citadel" (Lviv)

Aim of this work is to create a digital terrain model of defensive structures “Citadel” using archival and modern cartographic data and aerial images. Objectives of the work is to develop technological scheme and describe the method of creation of digital terrain model and configuration of its 3D-visualization. Methods. Contour lines with 2m interval was created using fragment of modern topographic plan of Lviv, namely the area “Citadel” with scale 1: 5000, Altitude matrix was created on its base. Using archived data: aerial image captured by Germans in 1944 and photo fixing of objects holistic view on the location of the area as at 1944 was obtained. Archival aerial image was geometrically transformed by a polynomial model of the second degree. After that, it were vectorized layers of buildings, road network, vegetation, fencing and supervisory towers of concentration camp Stalag-328 as at 1944. Object textures According to archive data of photo fixations concentration camp buildings, created. Textures for roofs of buildings were created on the basis of data obtained from satellite images captured GeoEye-1 satellite in 2010. Using all obtained data 3D-modeling of the territory and graphical reconstruction of concentration camp Stalag-328 was carried out. A joint processing of modern and archival data is the basis for constructing digital terrain model that transmits all the features of altitude and situational components of territory for the time of the existence of concentration camp Stalag-328. Results. We created the digital terrain model of the “Citadel” district in Lviv on the base of combined data from aerial images of 1944 and modern maps. Scientific novelty. The technological scheme of creation of digital terrain model based on archival material allows quickly visualize historically significant objects in their original form. The practical significance. Analysis of the constructed digital model made it possible to get an information about location of the objects of “Citadel” area as it was in 1944. The resulting digital terrain model can be used to display historical events that took place in the area. The results of this work can be transferred to the Department of preserving the cultural heritage of Lviv Regional Council for providing tourist information purposes.