Table 1.

Categorization of exposure risk factors

Risk factor (weight)	Spatial resolution	Temporal resolution	Data type	Coordinate system	Data source	Hypothetical link	Classification	π weights	Based upon
Elevation (0.03)	~ 30 m at equator	na	Raster	EPSG:4326	Aster GDEM V2 from USGS	While elevation decreases, the risk of infection increases	High risk: < 900 m	0.70	[32, 51, 56]
							Medium risk: 900–2300 m	0.25
							Low risk: > 2300 m	0.05
Land use (0.26)	~ 30 m	2-3-2017	Vector	EPSG:4326	OpenStreetMap project	Wet surfaces are more suitable to ahigher risk of infection	Very high risk: wet soils	0.42	[32, 57]
							High risk: water bodies	0.29
							High and medium risk: Agriculture land and grass	0.16
							Medium and low risk: forest and natural areas	0.08
							Low risk: barren land	0.02
							Very low risk: built land	0.03
Slope (0.13)	~ 30 m at equator	na	Raster	EPSG:4326	Derived from elevation	At more flat surfaces the risk of infection increases	High risk: < 11 degrees	0.70	[49, 51]
							Medium risk: 11–30 degrees	0.23
							Low risk: > 30 degrees	0.07
Distance to water bodies (0.50)	30 m	2-3-2017	Raster	EPSG:32651	Derived from roads, urban areas, river network and water bodies from the OpenStreetMap project	While distance to water bodies decreases, the risk of infection increases	High risk: < 1000 m	0.74	[51, 52, 58]
							Medium risk: 1000–5000 m	0.21
							Low risk: > 5000 m	0.05
Snail infection rate (0.06)	na	2015–2016	Vector	EPSG:4326	Derived from recorded surveys	While snail infection rate increases, the risk of infection increases	High risk: > 3.6%	0.65	[23, 24, 30, 31]
							Medium risk: 0.5–3.6%	0.28
							Low risk: < 0.5%	0.07

Abbreviation: na, not applicable