2,956
edits
Archive:000/Land/built-up: Difference between revisions
m
Elie moved page Land/built-up to Archive:000/Land/built-up without leaving a redirect: Huge_refactor
(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...") |
m (Elie moved page Land/built-up to Archive:000/Land/built-up without leaving a redirect: Huge_refactor) |
||
| (2 intermediate revisions by the same user not shown) | |||
| Line 16: | Line 16: | ||
|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 | |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 know of actual data, please tell us in the {{Talk}}. | ||
}} | }} | ||
{{dp | {{dp | ||
| Line 33: | Line 33: | ||
Any land with fewer people, will be counted proportionally. So if the population density is 10% of the threshold, we say the area contains 10% built-up land. This might be the case of a small family farm, where 90% of the lot is farm land, and the last 10% is housing and driveway. | Any land with fewer people, will be counted proportionally. So if the population density is 10% of the threshold, we say the area contains 10% built-up land. This might be the case of a small family farm, where 90% of the lot is farm land, and the last 10% is housing and driveway. | ||
Technically, there could be fully-built-up areas below this population threshold - such as industrial areas - but those are probably uncommon enough. | Technically, there could be fully-built-up areas below this population threshold - such as industrial areas - but those are probably uncommon enough. | ||
pop << data/population.data-float64-8640x4320 # population counts | |||
Let's test out our threshold using the [[Code:isochromic.c|image generator]]: | |||
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{{p|probably because their definition is more strict:<br /><br />"'Built-up' is defined as the presence of buildings (roofed structures). This definition largely excludes other parts of urban environments and the human footprint such as paved surfaces (roads, parking lots), commercial and industrial sites (ports, landfills, quarries, runways) and urban green spaces (parks, gardens). Consequently, such built-up area may be quite different from other urban area data that use alternative definitions."}}, 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}}. | |||