【Objective】Effects of topographic factors on soil erosion in southern red soil region with serious soil and water loss problem were studied.【Method】Southern Jiangxi was taken as the typical sample area.Topographic factors were extracted from the recut map dataset with a 5km extension of obtained 1∶ 100 000map by merging 1∶100 000sheet map of this region with 16 1∶50 000maps of surrounding areas.Based on Hc-DEM and a slope median filtration with 50m×50mneighborhood window,the Southern Jiangxi region was cate...