comparison of landform classifications of elevation, slope, relief and curvature with topographic position index in the south of bojnoord

the aim of the study is the classification of landform based on elevation, slope, relief and curvature inputs (old method) and topographic position index (tpi) (new method) in the south of bojnoord. the input data for the two methods is a digital elevation model (dem). the results of topographic position index (tpi) model showed that most area of landform were covered by class 5 (plains small) and the lowest area of landform was covered with open slope (class 6) (< 0.1%). the results of landform classification using elevation, slope, relief and curvature showed that the upper terraces (shoulder) were located in the many parts of the study area (green color). plateau (back slope) landform was located in center, some parts of the west and south of the study area. in general, with increasing slope and elevation different types of landforms occur. thus slope, elevation, relief and curvature are effective in preparing the landform classification map. the comparison of the two methods showed that the tpi method was more accurate because the method revealed more details.