Military-geographical characteristics of the physical factors of the land border of the Republic of Croatia

This paper systematically quantifies, for the first time, the relationship between physical–geographical features and the stability of Croatia’s state borders, and demonstrates the importance of physical-geographical barriers in shaping and maintaining the stability of the land borders of the Republic of Croatia (RoC). A GIS analysis of tactical significance was conducted using a topologically-oriented method of matching two entities: the border itself, and relevant physical-geographical and military-geographical factors. It was established that prominent physical-geographical features define 58.6% of the border (45% rivers, 14.3% valleys, and 7.6% ridges). Historical shifts in river courses prompted further analysis, and by extending the observation zone along river courses by 3 km, the share of physical-geographical features increased to 75%, thereby confirming the decisive role of rivers in the formation of demarcation lines. Naturally-determined sections (the Sava River, Kupa River, Drava River, Danube River, Sniježnica Mountain, Ravna Gora Mountain, etc.) have proven to be factors of stability and security throughout history, whereas administrative borders were subject to change, particularly in Banovina, Kordun, Istria, and western Srijem.