Gis-based multi-criteria analysis: selecting property locations with ahp and topsis
Explore how GIS combines with MCDA, why AHP and TOPSIS serve different purposes, and why mandatory screening should precede ranking.
Site selection involves competing criteria such as accessibility, land cost, market demand, infrastructure, hazards, and legal requirements.
Apply hard constraints before scoring
Legal ineligibility or incompatibility with intended use should not be offset by high accessibility scores. Screen out infeasible sites first.
Then design a criteria hierarchy and avoid double counting correlated attributes.
AHP and TOPSIS answer different questions
AHP uses pairwise comparisons to support criteria weighting, with a review of judgement consistency. TOPSIS ranks alternatives by their distances from ideal and anti-ideal solutions using a normalised decision matrix.
Results are sensitive to the criteria, normalisation methods, weights, and input data. No single method is universally best.
GIS provides spatial evidence
GIS can measure proximity, catchments, hazard layers and local amenities. Document data sources, coordinate reference systems, and update dates.
Conduct sensitivity analysis on weights and confirm key assumptions through fieldwork.
Rank three hypothetical sites using four GIS-related criteria, apply eligibility gates, and test whether small changes in weights alter the ranking.
MCDA makes trade-offs explicit; it does not replace legal due diligence, site inspections, or accountable judgement.
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This introductory article is adapted from the BDSNL knowledge series. Read the complete lesson and related resources at the links below.