OpenStreetMap
In South Wales there is the town Haverfordwest and the city St Davids. Mapnik renders St Davids and not Haverfordwest when zoomed out, which is correct behaviour. However St Davids is only a city because it has a cathedral, in all other aspects Haverfordwest is a more important place and is the principal town of the county. Once you do zoom into Haverfordwest, the name of a suburb (Alberts Town) seems to take priority over the town name at certain zoom levels.
There are similar issues with rail lines and train stations. The data available doesn't say which stations are the important ones, and whilst I could theoretically pull data from somewhere on number of trains per day it still wouldn't be entirely accurate and the map wouldn't be entirely open.
So, suggestions on fixing any of this would be appreciated.
Discussion
Comment from davidearl on 21 гыйнвар 2009 сәгать 15:05
This issue has arisen a number of times on the talk list. Here's my opinion:
In some ways it's like the distinction between the formal designation of a road by some authority and what it looks like to a surveyor on the ground. Most of the time they agree (trunk road is signed as such), but sometimes they differ. Most cities are also large (in the UK) but some are not (Ely is another example, though not quite as extreme as St Davids). In the US nearly all incorporated settlements are "cities". So really we need some clue as to the importance of a settlement in order to solve these rendering problems; at present the place= designation is synonymous with importance, so nealry all US cities are tagged as town or village. Without a widely adopted alternative tagging scheme, we can't really do any better and St David's ought to be downgraded according to its importance (which given its history is probably more than just a village despite its size) despite its formal designation. Population has been suggested as an alternative, but (a) this information is copyright in the UK and (b) some places punch above their weight (e.g Hay-on-Wye is definitely a town not least in the eyes of the inhabitants even though it has fewer than 2000 people). Approximate area might be another one, not copyright and possibly computable but does still suffer from point b. Probably some combination of factors is the answer, but so far we only have place= to go on in any widely adopted way.
Comment from kaerast on 21 гыйнвар 2009 сәгать 15:28
I've been following the talk list, but not seen any real outcome. Based upon the wiki page for key:place, St Davids should be demoted to village (population below 10,000) but then it would be technically wrong and wouldn't get rendered until too high a level zoom.
I understand about the whole not tagging for the renderer, but maybe a way of telling Mapnik which places are more important to display is better than the technicalities of what is and isn't a city.
Comment from kaerast on 21 гыйнвар 2009 сәгать 15:28
I've been following the talk list, but not seen any real outcome. Based upon the wiki page for key:place, St Davids should be demoted to village (population below 10,000) but then it would be technically wrong and wouldn't get rendered until too high a level zoom.
I understand about the whole not tagging for the renderer, but maybe a way of telling Mapnik which places are more important to display is better than the technicalities of what is and isn't a city.
Comment from RichardB on 21 гыйнвар 2009 сәгать 18:59
Just to put the record straight here - St. David's is a city *NOT* because it has a cathedral. That hasn't been used as a way of determining which place is a city or not for around 150 years.
St. David's became a city only in 1994. City status is awarded by the monarch and usually places apply to be considered upon special events.
e.g. the last two times when a town could apply to become a city were in the Millennium in 2000 and for the Queen's Golden Jubilee in 2002.
Comment from RichardB on 21 гыйнвар 2009 сәгать 19:03
Oh, and population is a bad way of determining importance on the map. A town of 10,000 people near to a major city is often insignificant locally, but a town of 1,000 people in rural Wales at the junction of two or more major roads is very significant locally. Judgement is required, not raw population figures (even if we could get that information free from copyright)