What is slope, and why is it important?

Slope can be defined as the angle, inclination, steepness, or gradient of a straight line. Slope often is used to describe the steepness of the ground’s surface. Slope can be measured as the rise (the increase in elevation in some unit of measure) over the run (the horizontal distance measured in the same units as the rise). Many geographic information systems (GIS) can analyze digital elevation data (elevation points, contour lines, digital elevation models, etc.) and derive both slope and aspect data sets. Slope is an important landscape metric. Some examples of its applications include:
– to help describe landforms,
– to model surface runoff,
– to characterize habitat,
– to classify soils,
– to assess the potential for development, and
– to model wildfire risk.