Aspect computation
Introduction
Slope aspect can be computed from the normalized gradients (see Slope computation page). It can be shown that for the slope aspect ψ we have:
Readers are warned that this formula should not be carelessly replaced by using:
the reason being that the latter formula does not account for southeast and southwest quadrants, nor for cases where δf ∕ δy = 0. (In the first situation, one must add 180∘ to the computed angle to obtain an angle measured from North; in the latter situation, ψ equals either 90∘ or -90∘, depending on the sign of δf ∕ δx.)
Learning outcomes
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11 - Spatial analysis: classes of functions
Classify and explain spatial analysis functions (measurements, classification, overlay, neighbourhood and connectivity) in a raster and vector environment (level 1 and 2).
Prior knowledge
Outgoing relations
- Aspect computation is a kind of Surface Analysis