Landform refers to the shape of the Earth's surface, and is the result of processes operating both beneath the Earth surface (tectonic forces) and those affecting the land from above (gradational forces). Tectonic forces usually force the surface upwards or change its structure, while gradation forces usually break it down and even out the level of the land. Individual landform features are often classified into residual, erosional or depositional by the way these gradational forces have affected the initial surface.
Residual features - are those remaining after, or resisting gradation.
Erosional features - are created where material has been removed.
Depositional features - consist of material relocating following its erosion.