Stirred, not shaken: genetic structure of the intermediate snail host Oncomelania hupensis robertsoni in an historically endemic schistosomiasis area

Table 4 Distance models applied

	Components
Distance model	Off-stream weight*	Slope	Model description
Euclidean distance
Euclidean distance	1	N/A	Straight-line distance
Isotropic least-cost distance
Cost distance	10	N/A	Isotropic least-cost path distance
Proportions	10	N/A	Proportion of the path that consists of on-stream segments
Onstream segments	10	N/A	Cumulative distance of on-stream segments along least-cost path
Total path	10	N/A	Cumulative, unweighted distance along least-cost path
Anisotropic least-cost distance
Linear 1:10	10	Linear increase; 1 at most negative slope, 10 at most positive slope	Anisotropic least-cost path distance
Linear 1:10 proportion	10	Linear increase; 1 at most negative slope, 10 at most positive slope	Proportion of on-stream segments
Binary 1:10	10	Negative slope: 1 Positive slope: 10	Anisotropic least-cost path distance
Binary 1:10 proportion	10	Negative slope: 1 Positive slope: 10	Proportion of on-stream segments
Linear 1:100	100	Linear increase; 1 at most negative slope, 10 at most positive slope	Anisotropic least-cost path distance
Linear 1:100 proportion	100	Linear increase; 1 at most negative slope, 10 at most positive slope	Proportion of on-stream segments
Binary 1:100	100	Negative slope: 1 Positive slope: 10	Anisotropic least-cost path distance
Binary 1:100 proportion	100	Negative slope: 1 Positive slope: 10	Proportion of on-stream segments

Alternative geographic distance variables estimated between all pairs of sampling sites. *Relative to on-stream segments.

ISSN: 1756-3305