Sky-view factor enhanced doline delineation: A comparative methodological review based on case studies in Slovenia

Abstract

This study presents a novel method for the accurate delineation of dolines in karst areas. The method is based on the use of hydrological tools and sky-view Factor in ArcGIS Pro and was implemented using a digital elevation model with a resolution of 1 m in four study areas in Slovenia. We manually delineated dolines at four test areas and compared them with the results of the new method, as well as the results of the most commonly used method of hydrological filling and the results of U-Net segmentation. We calculated the average deviation of the perimeter and the differences in the basic morphometric properties. The hydrological filling method cannot be accepted as a suitable method for doline delineation and should only be used for doline identification. The method based on the U-Net segmentation performed better, but the results contain landforms that are not enclosed depressions and therefore cannot be considered as dolines. The new method utilizes the advantages of hydrological filling and at the same time improves the doline delineation. We conclude that the presented method is the most suitable for automatic doline identification and delineation among the automatic methods discussed in this paper. This study further quantifies the enhancements achieved with the new method, highlighting the specific improvements in perimeter accuracy and the reliability of morphometric measurements.