Spatial Overlay Analysis
A foundational GIS method for examining how locations, features and environmental conditions intersect.
Spatial overlay analysis combines two or more geographic layers to examine where features coincide or relate. The method can support environmental screening, pattern identification and the organisation of evidence for further assessment.
How to use it responsibly
The analytical question should determine which layers, spatial relationship and scale are appropriate. Before interpretation, datasets need to be checked for coverage, date, resolution, coordinate system and known limitations.
An overlap is evidence of spatial coincidence. It does not automatically demonstrate dependency, impact, exposure or risk. Those conclusions require suitable contextual information and a clear causal argument.