Figure 7. Raster analysis by pixels to examine the presence of spatial barriers to Plasmodium falciparum movement in a geographically defined region of western Kenya.

( A) Each pixel represents a 10km-by-10km area of the region, and is colour-coded based on the coefficient estimates derived from a linear regression analysis that was used to test the impact of each pixel in acting as either a barrier (blue pixels) or gateway (red pixels) to parasite movement with the region. No pixels were significant barriers or gateways to parasite movement after Bonferroni correction to account for multiple comparisons. ( B) Distribution of p values observed after bootstrapping the regression analysis (with 10,000 resampling steps) to determine the level of significance of pixels in acting as barriers to parasite movement. ( C) Moran’s I analysis describing the spatial autocorrelation between geographical locations of pixels and their associated coefficient estimates. Autocorrelation was calculated for parasites grouped in 10km distance bands, and the analysis was bootstrapped 100 times to determine significance.