SDSAfrica

Multi-criteria spatial analysis (1/6)

In today’s post, we are doing something a bit more technical. Functional Area index modelling
• The Functional Areas are based on existing data and information to ensure a link between current conditions and future development. This index should serve as an essential input into the decision-making process to guide development and direct the Capital Expenditure Framework’s priorities.
• The aggregate of the Functional Areas describes a development potential framework. It provides a realistic representation of the municipality’s current situation to compare and measure the spatial efficiency of the existing municipal spatial policies and strategies.
• Steps in a multi-criteria analysis
• Below are the necessary steps followed in a multi-criteria evaluation.
o Define the problem/question: Clearly define the goal or issue the analysis needs to address.
o Determine the criteria: What factors and constraints need to be considered?
o Standardise the factors: Normalisation process that allows various criteria to be compared.
o Normalisation is typically done by ranking the factors in an index (i.e. 1 to 10) from high to low or good to bad.
o Determine each factor’s weight: Decide its impact and express it as a weighted percentage against the other elements.
o Aggregate the criteria: Various methods are used, of which weighted overlay or arithmetic overlay is most commonly used to get a final suitability result.
o Validate/verify the result: Involves checking the results and adjusting the criteria’ weightings if needed.
o The Functional Area model methodology and results
o The suitability model is presented in Figure 5. The final index comprises five (5) primary criteria (sub-indexes), each containing several data and information inputs. Each measure has a weighting of 100, which shows its impact on the final results.
o The five main criteria include urban morphology, access to facilities, demographic influence, economic influence, and environmental impact.
• The subsequent sub-section and maps show the results of the analysis. The maps show the results of the variables considered in the development of each index map.