Archive:000/Land/built-up - Revision history

Elie: Elie moved page Land/built-up to Archive:000/Land/built-up without leaving a redirect: Huge_refactor

2024-10-26T20:29:49Z

Elie moved page Land/built-up to Archive:000/Land/built-up without leaving a redirect: Huge_refactor

← Older revision	Revision as of 15:29, 26 October 2024
(No difference)

Elie at 05:51, 30 August 2022

2022-08-30T05:51:47Z

← Older revision		Revision as of 00:51, 30 August 2022
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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 {{~~TALK~~}}.		\|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
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	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.~~<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.

			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 << 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'
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	The <code>Sum: 2708207.986793</code> is the number of km<sup>2</sup> of built-up land on Earth.		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>.		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}}.		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}}.

Elie at 05:20, 30 August 2022

2022-08-30T05:20:15Z

← Older revision		Revision as of 00:20, 30 August 2022
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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 {{~~TALKPAGENAME\|talk page~~}}.		\|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 /= ~~5000~~ # threshold for land to be considered 'fully built-up'		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
	~~The "sum" (which will appear in~~ the result ~~from the last line~~) ~~will be the number of km^2 of built~~-~~up land on Earth~~.		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]

	~~Compare this to~~ official estimates...		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}}.

Elie: 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..."

2022-08-29T22:16:49Z

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..."

New page

==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 estimate the ''minimum'' population density that might be considered fully built-up land:

{{dp
|suburban_lot_size
|5000 ft^2
|
|"Large, 5,000 square foot lots, on the other hand, are the standard in US post-war suburbs." Do Minimum Lot Size Rules Matter? - Strong Towns www.strongtowns.org › journal › do-minimum-lot-size-rules-matter
}}
{{dp
|housing_fraction
|40%
|What fraction of the suburban land is housing
|The rest would be roads, parks, parking lots, and a small number of commercial buildings. This is just an educated guess, so if you have actual data, please say it in the {{TALKPAGENAME|talk page}}.
}}
{{dp
|household_size
|3 people
|Average number of people living in a house, in our low-density suburb
|This is intentionally a low estimate because we want to know the ''minimum'' population density for fully-built-up land.
}}
{{calc
|household_size * housing_fraction / suburban_lot_size
|people per km^2
}}

So, any land with more people than this, would be considered 100% built-up land in our analysis.

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. Let's test out our threshold using the [[Code:isochromic.c|image generator]]:
pop << data/population.data-float64-8640x4320 # population counts
pop @@ quantity_to_density # convert to 'people per km^2'
pop /= 5000 # threshold for land to be considered 'fully built-up'
pop <= 1
pop @@ density_to_quantity
pop @@ stats
The "sum" (which will appear in the result from the last line) will be the number of km^2 of built-up land on Earth.

Compare this to official estimates...