Aspect

Aspect identifies the orientation or direction of slope. Aspect is the down-slope direction of a cell to its neighbors.

The cell values in an aspect grid are compass directions ranging from 0 to 360. North is 0 and in a clockwise direction, 90 is east, 180 is south, and 270 is west. Input grid cells that have 0 slope (flat areas) are assigned an aspect value of -1.

Aspect is the compass direction toward which a section of surface is pointing. In this example, red represents slopes facing north and yellow shows slopes facing east.

A cell with an aspect value of 90 is angled or facing east. If you walked down that hill, you would be walking east. This cell would get lots of sun in the morning as the sun rises, and less sun in the evening because the sun sets in the west.