Citation: Ðor ¯ devi´ c, D.R.; Ðuri´ c, U.M.; Bakraˇ c, S.T.; Drobnjak, S.M.; Radojˇ ci´ c, S. Using Historical Aerial Photography in Landslide Monitoring: Umka Case Study, Serbia. Land 2022, 11, 2282. https:// doi.org/10.3390/land11122282 Academic Editors: Domenico Calcaterra, Diego Di Martire, Luigi Guerriero and Roberto Tomás Received: 15 November 2022 Accepted: 9 December 2022 Published: 13 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). land Article Using Historical Aerial Photography in Landslide Monitoring: Umka Case Study, Serbia Dejan Radovan Ðor ¯ devi´ c 1,2,† , Uroš Ðuri´ c 3,† , Saša Tomislav Bakraˇ c 1,2, *, Siniša Milanko Drobnjak 1,2, * and Stevan Radojˇ ci´ c 1,4 1 Military Geographical Institute, Mije Kovaˇ cevi´ ca St. 5, 11000 Belgrade, Serbia 2 Military Academy, University of Defense, Generala Pavla Juriši´ ca Šturma St. 33, 11000 Belgrade, Serbia 3 Faculty of Civil Engineering, University of Belgrade, Bulevar kralja Aleksandra St. 73, 11000 Belgrade, Serbia 4 Academy of Technical and Art Applied Studies, School of Civil Engineering and Geodesy, Milana Raki´ ca St. 42, 11000 Belgrade, Serbia * Correspondence: sasa.bakrac@vs.rs or sbakrac2017@gmail.com (S.T.B.); sinisa.drobnjak@vs.rs or sdrobnjak81@gmail.com (S.M.D.); Tel.: +381-113205007 (S.T.B. & S.M.D.) † These authors contributed equally to this work. Abstract: The application of remote sensing methods provides useful information that can be used for numerous research. Thus, spatial changes in soil, vegetation, hydrography and such can be analyzed. By analyzing the data obtained by remote sensing methods, high-quality and important data can be obtained for monitoring changes in soil movement caused by landslides. This method provides the possibility of determining the state of the observed space over a longer period of time. Historical aerial imagery has a high level of spatial detail analysis. Comparative analysis of the aerial imagery from the past, recent ones and other surveys can certainly provide information on the trend of ground movement, as well as lead to conclusions for taking specific measures. The present paper gives an example of the analysis of the particular area of the “Umka” landslide based on historical surveys. The “Umka” landslide is located along the right bank of the Sava River near the city of Belgrade, which, with its long-term activity, jeopardizes residential buildings, infrastructure facilities and the population that still lives on it. Keywords: aerial photography; photography processing; landslide monitoring; remote sensing 1. Introduction Aerial photogrammetry as a remote sensing technique provides the capacity for reconstructing the topographic features of the terrain, which was previously photographed from the air. Thus, by analyzing aerial photographs [1,2], important and high-quality information about the space and its previous and current state can be obtained with great precision. Aerial photographs from previous and current epochs, with equipment for processing and presenting spatial data, provide the possibility of multipurpose use [3,4]. Therefore, it is possible to analyze the displacements of terrain surface (landslides), or such as changes in vegetation, hydrography, infrastructure, settlements and such phenomena [5]. In terms of monitoring landslides, very useful information can be obtained through the process of interpreting the relationship between the present and the previous situation, as well as through the extent and prediction of changes. The advantages of this method of data collection, compared to other forms, including satellite imaging, are complete autonomy in operation, cost and the possibility of analyzing the state of the space from significantly earlier recording periods [6–9]. The subject matter of the research in the present paper is the “Umka” landslide near Belgrade. The research was designed with the aim of obtaining answers about the geomorphologic and morphometric changes of this landslide over time, based on historical aerial photographs. The aim of the paper is to present this analysis as a methodological Land 2022, 11, 2282. https://doi.org/10.3390/land11122282 https://www.mdpi.com/journal/land