[Talk-us] Correct source for population=* tags on US metropolitan cities

[Joseph Eisenberg]

Re: > In this scheme, is the place node totally separate from the boundary
relation?  If so, this approach strikes me as fine.

I believe that is reasonable to add population=* tags directly to
administrative boundaries (boundary=administrative relations), when this
information is widely available from a public source, such as the
government census.

For suburban towns and cities, as well as small towns and villages, which
are usually the only municipality in their own urbanized area (continuous
area of developed land), then using the municipal or township population
figures is fine. It will be close enough.

I personally don't add admin_center nodes to boundary relations, because
the place=* node is representing the cultural center of a named settlement,
while an administrative boundary is a legal entity. Tagging the capitol or
town hall object with admin_level=4 or admin_level=8 should make it clear.

On Sat, Jan 9, 2021 at 3:01 PM Brian M. Sperlongano <zelonewolf at gmail.com>
wrote:

> In this scheme, is the place node totally separate from the boundary
> relation?  If so, this approach strikes me as fine.
>
> If the node is attached to a boundary (as an admin_centre or label role),
> I wonder if that might have any unintended effects on consumers of
> population data.
>
> On Sat, Jan 9, 2021 at 5:50 PM Joseph Eisenberg <
> joseph.eisenberg at gmail.com> wrote:
>
>> Proposal:
>> Use the census data on Urbanized Areas to set the "population=" value for
>> "place=city" nodes, rather than using the whole metro population or just
>> the population of the central municipality.
>>
>> Rationale:
>> The tag "population=*" is helpful as a way to distinguish small
>> place=city features (which might have less than 50,000 people in rural
>> States) from huge cities. Many database users depend on this information
>> for rendering decisions at low zoom levels (large scales) and as a general
>> estimation of the "importance" of a place.
>>
>> However, currently most population figures are taken from the population
>> in the municipal boundaries, since this is often what is on local signs and
>> easily available from the census. While this is fine for towns and small
>> cities which are contained in one municipality, it often misses
>> unincorporated urban areas next to the city limits, and for large cities it
>> badly underestimates the population of the area which is considered part of
>> the "place".
>>
>> For example, many people in West Hollywood or East Los Angeles would
>> consider that they live in the larger place "Los Angeles", even though they
>> live in a different municipality or an unincorporated area. Someone who
>> lives in Vancouver, Washington will often tell people they live "In
>> Portland" when talking to someone from outside of the region, since it
>> functions as a suburb of the Portland, Oregon metro area.
>>
>> So I propose that we should use an estimate of the urban population for
>> the population=* tag when tagging metropolitan places. Usually this will
>> lead to a larger population number, except in rare cases like Anchorage.
>>
>> In particular, I would like to use the US Census "urbanized area"
>> figures, since these are much more sensible than the numbers from
>> metropolitan areas based on county boundaries which can include distant
>> towns and rural areas.
>>
>> This would mean that the place=city node for Portland, Oregon would have
>> population=2072553 (representing the whole urbanized area) rather than just
>> 654000 from the city limits.
>> https://censusreporter.org/profiles/40000US71317-portland-or-wa-urbanized-area/
>>
>> Minneapolis, MN would have population=2885614 instead of only 429k
>> https://censusreporter.org/profiles/40000US57628-minneapolis-st-paul-mn-wi-urbanized-area/
>>
>>
>> But Anchorage would decrease slightly from 288k to 249K
>> https://censusreporter.org/profiles/40000US02305-anchorage-ak-urbanized-area/
>>
>> Usually the difference would not change the relative rank of cities very
>> much, but it would be good to have the population figure map the
>> OpenStreetMap "place" concept, rather than the city limit boundaries.
>>
>> Eventually this could improve maps of the USA and help them better match
>> those in other countries, where city limits tend to be much larger than in
>> the case of many US cities, which often have many separate municipalities
>> for suburbs.
>>
>> Of course it will still be appropriate to add the precise population=* to
>> the boundary=administrative feature which represents the municipality, and
>> database users could choose to emphasize those features instead.
>>
>> -- Joseph Eisenberg
>>
>> PS: the 2010 population figures of US Urbanized Areas are on wikipedia,
>> and this year we will get updated 2020 figures, so it would be a good time
>> to make this change. The biggest difference will be for Miami, Florida,
>> where the central municipality is only 7% of the population of the whole
>> urbanized area:
>> https://en.wikipedia.org/wiki/List_of_United_States_urban_areas
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>
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