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Land/built-up: Difference between revisions
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(Created page with " ==Using 'population' data to estimate built-up land== Some inner cities can be quite dense, but even the less-dense suburbs are still fully ''built-up'', as none of the land is truly ''wilderness'' {{x|even the parks and nature trails are heavily touched by humans}}, and none of it is considered farm land {{x|maybe this could change with suburban farming, but even then, maybe double-counting the same land (as ''both'' cropland ''and'' built-up land) is ok}}. Let's est...") |
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|40% | |40% | ||
|What fraction of the suburban land is housing | |What fraction of the suburban land is housing | ||
|The rest would be roads, parks, parking lots, and a small number of commercial buildings.<br /><br />This is just an educated guess, so if you have actual data, please say it in the {{ | |The rest would be roads, parks, parking lots, and a small number of commercial buildings.<br /><br />This is just an educated guess, so if you have actual data, please say it in the {{TALK}}. | ||
}} | }} | ||
{{dp | {{dp | ||
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Technically, there could be fully-built-up areas below this population threshold - such as industrial areas - but those are probably uncommon enough.<br />Let's test out our threshold using the [[Code:isochromic.c|image generator]]: | Technically, there could be fully-built-up areas below this population threshold - such as industrial areas - but those are probably uncommon enough.<br />Let's test out our threshold using the [[Code:isochromic.c|image generator]]: | ||
pop << data/population.data-float64-8640x4320 # population counts | pop << data/[[:File:population.data-float64-8640x4320|population.data-float64-8640x4320]] # population counts | ||
pop @@ quantity_to_density # convert to 'people per km^2' | pop @@ quantity_to_density # convert to 'people per km^2' | ||
pop /= | pop /= 2583.3385 # threshold for land to be considered 'fully built-up' | ||
pop <= 1 | pop <= 1 | ||
pop @@ density_to_quantity | pop @@ density_to_quantity | ||
pop @@ stats | pop @@ stats | ||
Which gives the result: | |||
Dimensions: 8640 by 4320 | |||
'''Sum: 2708207.986793''' | |||
Average (Mean): 0.072558 | |||
Standard Deviation: (+/-) 0.651528 | |||
Minimum: 0.000000 at [0,0] | |||
Maximum: 21.466134 at [3093,2159] | |||
The <code>Sum: 2708207.986793</code> is the number of km<sup>2</sup> of built-up land on Earth. | |||
This is actually quite a lot higher than official estimates. [https://stats.oecd.org/Index.aspx?DataSetCode=BUILT_UP OECD] data says there's 784841 km<sup>2</sup> of built-up land globally, and [https://ourworldindata.org/land-use OurWorldInData] says there's about 1.5 million km<sup>2</sup>. | |||
Either way, built-up land is a tiny fraction of {{p2|Earth's surface|510 million km<sup>2</sup>, according to the same OurWorldInData source}}, especially compared to {{p2|farm land|43 million km<sup>2</sup>, according to the same OurWorldInData source}}. | |||