Biodiversity and WorldMap

UPPER ROW:

Equal-interval score scale 
(see histogram of score frequencies against colour scale) 
this gives the same range of score values to each colour class, but because the scores from some measures are inherantly highly skewed towards low values for widespread species, the maps may be predominantly dark blue and uninformative

LOWER ROW:

Equal-frequency score scale 
(see histogram) 
this gives the same number of grid cells to each colour class, which with the same scores has the effect of distinguishing subtle differences in scores among areas

difference
sum for all spp in cell of (C-c)

inverse

sum for all spp in cell of (1/c)

inverse square

sum for all spp in cell of (1/c²)

inverse minimum

sum for all spp in cell of (1/c_min)