Slope

Slope was determined from the DEM and using a variety of modules in IDRISI. Choosing a Boolean image for slopes was considered after conducting research on what was considered an appropriate range for a ski resort. Table 1 was taken from an online report written by David M. Rathke and Melvin J. Baughman on recreational trail design and construction. Although intended for hiking use, the similarities between the two sports are comparable.

Table 1. Description of Different Trail Grades.
Percent Grade Description
0 to 2
3 to 6
7 to 12
13 to 18
19 to 25
26 and greater		 Nearly level
Gently sloping
Moderately sloping
Moderately steep
Steep
Very steep

The decision then was to choose between 10-35%, dividing the terrain between beginner to highly expert skiing. The macro model for slope is as follows.

 

The resulting image is as follows: