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File:land-builtup1.png: Difference between revisions
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==Summary== | |||
Map of Earth with all built-up land shown in black. | |||
Made from [[:File:population.data-float64-8640x4320]] and [[:File:blue-marble-posterized.png]]. | |||
[[Code:isochromic.c|Image generator]] code: | |||
pop << data/population.data-float64-8640x4320 # population counts | |||
earth << data/blue-marble-posterized.png # base layer | |||
pop @@ quantity_to_density # converts population counts to density (people per km^2) | |||
pop /= 2500 # threshold (people per km^2) for land to be [[land/built-up|considered "fully built-up"]] | |||
pop <= 1 | |||
pop :: earth.r # resize to fit base layer | |||
earth.r -= pop | |||
earth.g -= pop | |||
earth.b -= pop | |||
earth.r @@ 01 | |||
earth.g @@ 01 | |||
earth.b @@ 01 | |||
earth >> data/land-builtup1.png | |||
Note: we are using population density as a ''best guess'' for determining which land is ''built-up''. In theory that might not be perfectly accurate, but in practice, the end result is matches ''well enough'' with totals from other data sources. | |||
==See also== | |||
* [[:File:land-crop1.png]] - crop land | |||
* [[:File:land-pasture1.png]] - pasture | |||
* [[:File:land-usage1.png]] - all land usage | |||
* [[:File:land-wild1.png]] - untouched lands | |||