GIS-based multi-criteria spatial decision support for equitable public toilet planning: mapping accessibility deficits, site suitability and priority intervention zones in Addis Ababa, Ethiopia

Abstract Rapid urbanization frequently outpaces sanitation infrastructure, leaving vulnerable residents without essential services. This study develops and applies a GIS-based spatial decision-support framework combining multi-criteria decision analysis (MCDA), the Analytical Hierarchy Process (AHP), and network-based accessibility analysis to assess location suitability and prioritize public toilet development in Addis Ababa, Ethiopia. Eight spatial criteria, population density, proximity to public activity nodes, road connectivity, distance from existing facilities, land use/land cover, slope, soil characteristics, and proximity to rivers were standardized on a 1–5 suitability scale. A field inventory of 339 georeferenced facilities, constraint masking, network service-area analysis, and sensitivity analysis produced three principal findings. First, accessibility is severely deficient: only 25.07% of residents (822,514 of 3,280,422) live within the normative 500 m walking distance to public toilets; 74.93% lies beyond it. Second, provision is maldistributed: the highest-density population class records a provision ratio of 0.90 against 1.39 in the second-highest, with Addis Ketema and Yeka each serving ~ 13,400 residents per facility. Third, expert weights are internally consistent (CR = 0.0152), with demand and accessibility criteria receiving 79.2% of total weight. Suitability mapping classified 20.46% of the city (87.97 km²) as high/very-high suitability. Overlaying suitability with service deficits and building-footprint constraints delineated a priority development envelope of 25.43 km² (5.91% of the city). Robustness testing across alternative weights and thresholds demonstrated stable spatial priorities (Jaccard similarity 0.60–0.97; AUC = 0.864). This framework provides municipal planners a transparent, reproducible basis for prioritizing sanitation investment, whilst acknowledging that tenure screening, community engagement, disability-responsive design, and environmental compliance remain essential.