Spatial Analysis

  • - Import constraint files and factors boolean files into Dicision Wizard. Set up land use rating factor as "Not Fuzzy" and other factors as "Fuzzy".

  • - Factors standardization:

Factors
 Function and Control Points Reasons
Slope Degrees Monotonically decreasing Sigmodial function; Control points at 10 and 76.9321 Area with slope lower than 10 degrees are easier to access and cheaper to construct. Slopes above 10 degrees are just equally unsuitable
Land Use Rating Pre-setup rating of all land use type: institutional=255, single home residential=200, low-rise residential=150, open undeveloped=100, others=0 Suitability rating base on accessibility, construction cost and safety.
Distance to Emergency Response Route Monotonically decreasing "J-shape" function; Control points at 100 and 500 Distance to the emergency response route within 100 m is best for delivering supplies and aid, the accessibility decrease beyond 100 m, 500 m is the mid point of not suitable and perfect suitable.
Distance to Natural Hazard Areas Monotonically increasing Sigmodial function; Control points at 500 and 1000 Due to safty concern, the further a place is away from the natural hazard areas, the more suitable a place is for building an emergency facility.
Population Density Monotonically increasing linear function; Control points at o and 22750.8 To build a emergency facility in an area with higher population density can serve more people when natural hazards happen. So the suitability increase with population density increase.

 

  • - In the next step of Decision Wizard, 5 standardized factor files are produced as the following raster images.

Picture 3.1 Land Use Rating

Picture 3.2 Distance to Natural Hazard Areas

Picture 3.3 Slope Degrees

Picture 3.4 Population Density

Picture 3.5 Distance to Emergency Response Route

  • - Next step of the analysis is to assign weights on each factor according to pairwise comparison weighing approach. The weight of each factor is determined by its relative importance (Picture 3.6).

    Picture 3.6

  • - The final step of Decision Wizard setting up is using Order Weighted Averaging method to ajust the level of risk taking and trade-off (see the table below).

  • - Run the Decision Wizard is all set and a suitable area raster image will be produced. The color palette represents the suitability rating of each cell in the image(Picture 3.7).

    Picture 3.7

 

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