As an essential factor of landform

slope gradient has impacted the processes of transformation of materials and energies.The main researches on slope have been reviewed

including slope mapping

slope effects of DEM type

slope scale effects involved to DEM resolutions

and transformation of coarser resolution DEM derived slope.The main problems puzzled researchers on slope is slope mapping methods

in which slope was thought of discrete data and mapping for each of the classes.These methods were not matched to development of GIS and DEM applications

and do not meet the requirements of modeling in watershed hydrology and regional soil erosion as well.Considering the application of slope in hydrology and regional erosion modeling

the vegetation suitability assessing and mapping

main topics to be studied on slope include effects of DEMs from varied interpolation strategies

mechanisms of reduction for coarser resolution DEMs derived slopes

methods and model for coarser slope transformation

and application of scaled slope surface in studies of hydrologic and erosion models at the regional scale.