Comparison of indexes for automatic mapping of built-up areas – a case study of Gliwice

Abstract

The built-up index was developed to "mapping" built-up areas using publicly available satellite images. However, its biggest problem is not distinguishing between built-up areas and bare soils. This distinction is fundamental to automatic mapping. Therefore, numerous approaches to delimitation appear in the literature, proposing different solutions to eliminate errors during the automatic process. The study aimed to select the most appropriate built-up index for automatic delimitation of areas related to the Upper Silesian Conurbation. Preliminary work was based on a literature review of the use of various built-up indexes. In the next step, the most useful indicators in the context of automatic delimitation of these areas were selected. In this work, comparative analyses of the built-up indexes proposed in the literature were carried out on the example of the city of Gliwice so that their usefulness and adequacy for the delimitation of built-up areas in the Upper Silesian conurbation could be determined. Analyses were carried out using open spatial data and using GIS tools such as ArcGIS and SAGA. Indicators were calculated using selected Landsat 7 and Landsat 8 satellite images. From the indicators selected, the MBUI appear to be the most useful, besides the basic one i.e., widely used in development de-limitation calculations, NDBI. However, each of these indicators has weaknesses that cause the automatic delimitation process generate some errors. There should therefore be further research in this area.