https://thechange.wiki/index.php?action=history&feed=atom&title=File%3Aland-usage1.png 2026-04-27T22:26:06Z Revision history for this page on the wiki MediaWiki 1.41.0 https://thechange.wiki/index.php?title=File:land-usage1.png&diff=320&oldid=prev 2022-08-30T13:35:05Z

<p>Elie uploaded <a href="/File:land-usage1.png" title="File:land-usage1.png">File:land-usage1.png</a></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <tr class="diff-title" lang="en"> <td colspan="1" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="1" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:35, 30 August 2022</td> </tr><tr><td colspan="2" class="diff-notice" lang="en"><div class="mw-diff-empty">(No difference)</div> </td></tr></table>

Elie https://thechange.wiki/index.php?title=File:land-usage1.png&diff=317&oldid=prev 2022-08-30T13:30:10Z

<p>Created page with &quot;==Summary== Black is farm land. Magenta is built-up land (housing etc) (which is hard to see except in China &amp; India). The rest could perhaps be considered &quot;untouched&quot; natural land. ==Methodology== <a href="/Code:isochromic.c" title="Code:isochromic.c">Image generator</a> code: pop &lt;&lt; data/population.data-float64-8640x4320 # population counts crop &lt;&lt; data/cropland.data-float32-4320x2160 # cropland fraction of land past &lt;&lt; data/pasture.data-float32-4320x2160 # pasture fraction of land earth&lt;&lt; dat...&quot;</p> <p><b>New page</b></p><div>==Summary==<br /> <br /> Black is farm land.<br /> Magenta is built-up land (housing etc) (which is hard to see except in China &amp; India).<br /> The rest could perhaps be considered &quot;untouched&quot; natural land.<br /> <br /> ==Methodology==<br /> [[Code:isochromic.c|Image generator]] code:<br /> pop &lt;&lt; data/population.data-float64-8640x4320 # population counts<br /> crop &lt;&lt; data/cropland.data-float32-4320x2160 # cropland fraction of land<br /> past &lt;&lt; data/pasture.data-float32-4320x2160 # pasture fraction of land<br /> earth&lt;&lt; data/blue-marble-posterized.png # base layer<br /> <br /> pop @@ quantity_to_density<br /> pop :: earth.r<br /> pop -= 400 # hard threshold (people per km^2) for land to be marked as 'built-up'<br /> pop @@ 01<br /> crop &gt;= 0<br /> crop @@ neg<br /> crop :: earth.r<br /> past &gt;= 0<br /> past @@ neg<br /> past :: earth.r<br /> <br /> earth.r *= crop<br /> earth.r *= past<br /> earth.r += pop<br /> earth.r @@ 01<br /> earth.g *= crop<br /> earth.g *= past<br /> earth.g -= pop<br /> earth.g @@ 01<br /> earth.b *= crop<br /> earth.b *= past<br /> earth.b += pop<br /> earth.b @@ 01<br /> earth &gt;&gt; data/land-usage1.png<br /> <br /> 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.<br /> <br /> ==See also==<br /> * [[:File:land-crop1.png]] - crop land<br /> * [[:File:land-pasture1.png]] - pasture<br /> * [[:File:land-builtup1.png]] - built-up land<br /> * [[:File:land-wild1.png]] - untouched lands</div>

Elie