Suitability Analysis and Fuzzy Logic
Andres Calderon
General overview
Part 1
How to deal with diverse cell size and CRS?
What about the extent of the study area?
i.e. Physical global datasets in degrees (WGS 84) [resolution: 0.9 arcsec]
i.e. Socio economic local indicators in metres (Pseudo-mercator) [resolution: 1Km]
Resampling
What we need as output…
We need to transform vector layers to raster…
We need to use the same spatial resolution (cell size)…
We need to clip and align to the same number of columns and rows…
Why?
Raster Algebra!
Part 2
How to compare layers from different aspects?
Ranges in data? Units? Relationship?
i.e. Coronavirus: 106 cases per 10K people.
i.e. Temperature: -20.7 celcius degrees.
Linear Fuzzification
What we need as output…
Each layer has to be ‘fuzzified’ to a range from 0 to 1 …
No more units, just how suitable each aspect is…
At this point we should have already dealt with outliers and null values…
Why?
Raster Algebra!
Part 3
Assign weights to each layer if needed.
Apply fuzzy overlay operations to aggregate the layers.
Filter regions with higher potential.
Raster Algebra
What we get as output…
A suitability map with values between 0 and 1 (we usually normalize it)…
Can be filter out according to a threshold…
Can be classified according to a criteria…
General Overview