Earthsys 144: Fundamentals of GIScience
Spatial Analytic Models
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(Analytic) Spatial Models
In general, analytic spatial models can be classed as:
- Cartographic Models
- Simple Spatial Models
- Spatial-temporal models
Cartographic Models
Cartographic Models
Ranking Criteria
Continuous Rank Layers
a) Sites should be far enough from a main road to offer some privacy, but not so far as to be isolated.
b) Slopes should not be too steep. Steep slopes may substantially increase costs or may preclude construction.
Relative Importance Ranking
AHP - Analytic Hierarchical Process
A Relative Ranking Method
Simple Spatial Models
Simple Spatial Models
Revised Universal Soil Loss Equation (RUSLE)
E=R*K*C*P*L*S
- E is average annual erosion,
- R is a rainfall factor,
- K reflects soil erodibility,
- C integrates crop/veg effects,
- P accounts for management practices,
- L reflects slope length, and
- S represents steepness.
Spatio-temporal Models
Often cell-based models
Tobler's Hiking Function
r=6exp(−3.5|S+0.05|)
r
= the walking rate in km/hr
S
= slope degrees
Tobler's Hiking Model
Tobler's Hiking Function
Models & 'Scripting'
QGIS Modeler
