The paper describes the automated calculation of Herfindahl–Hirschman Index of regional specialization. Having used GIS programming and Python programming language, a tool has been designed to enable the automated calculation and visualization of the results of the observed index within ArcGIS software environment. Apart from the definition of basic regional specialization terms and the description of mathematical concept of Herfindahl–Hirschman Index, the paper outlines the programming procedure for designing a tool for the automated calculation by describing the code writing procedure. The results provide an explanation and a practical instance of the tool application in Republic of Srpska.
