The SLASP algorithm uses the elevation layer in the input channel to calculate the corresponding slope and aspect angles. The results are written to two separate output channels.
| Result value | Description |
|---|---|
| Slope | At a point, slope is calculated as the slope of the plane formed by the vector connecting the left and right neighbors and the vector connecting the upper and lower neighbors of the pixel. Slope values always range from 0 to 90 degrees. |
| Aspect | At a point, aspect is calculated as the orientation of the plane formed by the vector connecting the left and right neighbors and the vector connecting the upper and lower neighbors of the pixel or the angle between the top of the image and the projection of the normal vector of this plane onto the horizontal plane. True aspect values always range from 0 to 360 degrees. |
| Zero slope aspect | Areas where the slope is zero are treated as a special case and are assigned a user-specified aspect value from the Zero slope aspect value input parameter. If this input parameter is not specified, a default value of 510 is assigned. |
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