Tomas Slancik

it's likely area in the image space units

image space is -1.-1 to 1,1 which is 2x2 with area 4
total amount of pixels is 1024x1024 = 1,048,576
so single pixel area is 4 / 1,048,576 = 0.0000038147
therefore your 53 pixel island area is 53 * 0.0000038147 = 0.000202179

EDIT: so if you are interested in the amount of pixels in the island based on the area value from statistics you can go backwards and do
0.000202179 * 1024 * 1024 / 4 = 53

as a workaround you can duplicate your geo and assign it volume shader with uniform volume property so that Karma will treat it as a volume

for reference have a look at kma_oceaninterior material inside of Houdini Procedural: Ocean

there is some earlier discussion about this here [www.sidefx.com] as well as some licensing implications