Wikipedia:Reference desk/Archives/Miscellaneous/2022 November 16

= November 16 =

How does Google Maps define "population areas"?
I'm curious about the light gray color that Google Maps uses to denote (supposedly) populated places. According to one website, it's for "population areas, cities, suburbs", but the actual implementation seems a little weird. In my area, for instance, [Smaller Town] borders [Larger Town], which borders [Regional City] – but even though [Larger Town] has roughly twice the population and density of [Smaller Town], and hosts more businesses, schools, etc., [Smaller Town] – along with [Regional City] – is shown as built-up light gray, while [Larger Town] is shown as rural green. What gives? Lazar Taxon (talk) 18:46, 16 November 2022 (UTC)
 * My guess is that it uses census tract data for this information. The U.S. census has its own definitions for what it defines as an "urban area" vs. a "rural area", and these do not often follow political boundaries.  The U.S. census calls these defined urban areas as a Census-designated place, and they are very common in areas local municipality boundaries do not closely mirror settlement patterns; for example in New England, where the census does not recognize New England towns as a legitimate municipality (despite being actual legal municipalities) because town lines do not often mirror settlement patterns, and towns often contain a mixture of urbanized and rural areas.  This also happens in areas of the U.S. where legal incorporation is not always done alongside population growth; for example in unincorporated places like Cleveland, Johnston County, North Carolina (near where I live), which has no municipal government, but which otherwise resembles "town" from its settlement pattern.  This information is, of course, specific to the U.S., but if you live in another country, Google is probably importing this data from whatever equivalent government body handles this sort of thing in your country, and for similar reasons.  -- Jayron 32 19:22, 16 November 2022 (UTC)
 * As a matter of fact, I am in New England – and you're right, it only shows the center of [Smaller Town] as built up, not the whole municipality. But I'm still baffled, because the center of [Larger Town] is, by any thinkable measure, more built up. Could it be that perhaps there's some measure of local prominence involved, and that [Smaller Town] is more "distinctively" built up owing to its greater distance from [Regional City]? Lazar Taxon (talk) 19:52, 16 November 2022 (UTC)
 * CDP definitions lag far behind "data on the ground" in my experience. I grew up in Hudson, New Hampshire, which has the smaller Hudson (CDP), New Hampshire.  AFAIK, the boundaries of the CDP have never been changed since I was a child in the 80s; since then the town has grown from mostly rural with a small dense core to mostly urban densities; so the CDP no longer represents the built-up area.  -- Jayron 32 20:04, 16 November 2022 (UTC)

Europe warmer than North America?
I've been looking up the weather for London, UK. I'm wondering why London is warmer than Calgary even though they're at similar latitudes? 67.215.28.226 (talk) 20:20, 16 November 2022 (UTC)
 * The immediate observation is altitude. Higher altitudes are generally colder. London is barely above sea level. Calgary is over 3,000 feet above sea level. 97.82.165.112 (talk) 20:27, 16 November 2022 (UTC)
 * See North Atlantic Current, a branch of the Gulf Stream. The mass movement of warm, tropical water northeast through the North Atlantic mediates the climate of Western Europe, making the temperatures milder than you find in other areas.  Calgary also has a Continental climate, which is known for wilder temperature swings (higher highs and lower lows) than coastal regions, generally speaking.  Climate is complex, and latitude is only a very rough predictor of climate; other factors (elevation, bodies of water, vegetation, etc.) often have as much or more of an effect.  -- Jayron 32 20:28, 16 November 2022 (UTC)
 * I see. Thank you. 67.215.28.226 (talk) 20:44, 16 November 2022 (UTC)

Further to Jayron's excellent comments, Calgary has a very high level of 'Continentality', while the UK does not. Calgary is explicitly listed at Continental_climate. When the UK suffers what the media often calls a "Siberian blast" or similar, it's because our usual westerlies have turned into easterlies and we get to feel a touch of what others in Europe experience in winter, even at much more southerly lattitudes.

It's the same within Europe. You can compare the climates of cities on or close to the 51st parallel north. Most tend to have much colder winters and much warmer summers than London. --Dweller (talk) Old fashioned is the new thing! 12:57, 17 November 2022 (UTC)
 * The effect of the Gulf Stream and its branches can also be seen by comparing coastal cities on similar latitudes... Boston and Pontevedra lie essentially directly across the Atlantic Ocean from each other along the 42nd parallel N. Boston has a daily mean annual temperature some 3 degrees celsius colder than Pontevedra.  Similarly, London lies on the same parallel of latitude as St. Anthony, Newfoundland and Labrador, and has a daily mean annual temperature of 11! degrees celsius colder than London.  The effect of the Gulf Stream on climate is massive.  Even looking at locales on the western edge of North America, where the similar Alaska Current, the Pacific analogue to the Gulf Stream, is, we see that Port Hardy, British Columbia, the nearest Pacific coast municipality I can find at a similar latitude to London, is about 3 degrees celsius cooler.  -- Jayron 32 13:14, 17 November 2022 (UTC)
 * Agreed, it's the Gulf Stream. Inverewe Garden in NW Scotland is able to grow sub-tropical plants, despite being on much the same latitude as the lower end of Hudson Bay and Kodiak Island, Alaska. Alansplodge (talk) 13:56, 17 November 2022 (UTC)