Which GIS overlay technique combines multiple criteria to assess suitability?

• A. Vector Overlay
• B. Raster Overlay
• C. Buffer Overlay
• D. Weighted Overlay Analysis using the Suitability methodology.

Answer: (D)

The method being tested is multicriteria suitability scoring, where several criteria are combined with assigned importance weights to judge how suitable a location is. Weighted Overlay Analysis uses a suitability methodology in which each criterion is reclassified to a common scale and given a weight that reflects its importance. The analysis then multiplies each criterion by its weight and sums the results to produce a single suitability score for every location. This explicit weighting and aggregation is why it’s the go-to approach for site selection and other suitability assessments, because it captures which factors matter more and integrates them into one map.

Other overlay approaches focus on geometry or simple data fusion rather than evaluating multiple criteria with relative importance. For example, vector or raster overlay methods combine layers based on spatial operations or cell-by-cell calculations without an intrinsic framework for weighting and scoring suitability. Buffering creates zones at a set distance around features and doesn’t inherently merge multiple criteria into a single suitability index.