Semi-automated recognition of planation surfacesand other flat landforms: a case study from theAggtelek Karst, Hungary

Abstract

This study deals with the possibilities of expertdrivensemi-automated recognition of planation surfacesand other flat landforms in the area of the Aggtelek Karst,Hungary. Planation surfaces are the most debatable andvague landforms and can be defined as parts of terrainformed by long-lasting erosion-denudation processes underthe stagnant erosion base conditions. In terms of denudationchronology they can be considered as morphologicalindicators of different evolution stages of area. Inkarst areas planation surfaces and river terraces are mostlycorrelated with cave levels, which originated in relation tothe same stagnant erosion base. Because there is no generalmethod of delineation of planation surfaces, the mainobjective of the study was to find a suitable method forsemi-automated recognition of flat landforms in the AggtelekKarst, which should correspond to different phasesof the Jósva River incision and therefore could be correlatedto the multilevel cave system of the study area.Several methods for semi-automated landform classificationwere tested for recognition of flat surfaces in a relativelyobjective way. Slope gradient thresholding tool, andr.param.scale and r.geomorphon modules implemented inGRASS GIS were tested. As a result, the r.geomorphonmodule was proven as the most suitable method for delineationof relatively flat surfaces. Findings of the presentedwork can be used as a morphological indicator ofthe comprehensive reconstruction of evolution of the AggtelekKarst and the Slovak Karst.

Keywords

• flat landform
• planation surface
• aggtelekkarst
• semi-automated recognition
• grass gis