[Talk-GB] too many universities in Cambridge

Dan S danstowell+osm at gmail.com
Fri May 22 11:27:02 UTC 2015


Hi David,

Thanks for the detailed info. My main concern is in terms of the
consequences for other data consumers. If someone tries to use OSM
data for anything - such as:
 (a) to plot the density of universities per county
 (b) to render a map using a UK-wide rendering scheme that indicates
each university prominently
- the results will be utterly wrong. So we do need some consistency,
at least at the country-wide level. (I'm pragmatic enough not to aim
for global consistency ;)

So I'm not offended, but I do care that our data is good for everyone.
I suggest that we should make a change but I will not rush anything!

I don't know what this "camp" is that didn't like building=university.
Was it an OSM camp (eg a discussion on the tagging email list)? Either
way, building=university is now used quite a lot worldwide
http://taginfo.openstreetmap.org/tags/building=university#map - I
think it's pretty uncontroversial as a building tag.

So the question, I guess, is what "jobs" amenity=university is doing
in your scheme. Is it being used as a selector for extracting data? Is
it being used as a selector for rendering-rules? You've got your
operator=* tagging which looks good for selecting a data extract.

If we made a two-step change such that all "building=yes,
amenity=university, operator=.*University of Cambridge.*" were first
modified to building=university, and then after a few months to remove
the amenity=university from buildings and leave it on
sites/universities/whatever-we-agree-it-should-be-on - would that work
for you? My quick overpass check suggests that would address about 800
of the 1200 objects.

Best
Dan


2015-05-22 11:54 GMT+01:00 David Earl <david at frankieandshadow.com>:
> Hi Dan,
>
> Yes, Philip's right - I developed and continue to maintain the University
> map at http://map.cam.ac.uk (as well as doing all of the original street
> pattern mapping for Cambridge back in 2006). The University has put a
> considerable investment and negotiated permission for college access into
> the map and contributed tens of thousands of pounds of survey data into OSM
> - it's not just "some of its maps", it's completely central to the
> University map, not just a casual effort.
>
> The "schema" for tags that make the University map work is at
> http://wiki.openstreetmap.org/wiki/Cambridge/University_of_Cambridge (I've
> just realised I haven't updated that page with a recent, unrelated new bit,
> I must do so).
>
> As it happens, I was also thinking about this the other day. The three main
> things are that is (a) consistent and (b) doesn't change under our feet and
> break the map, (c) it needs a way to distinguish these buildings from
> others. It possibly wasn't the best decision to do it like this, though I
> still don't think it is a terrible way to do it. Relations would be awful:
> they are very hard to maintain accurately, and incidentally they are hard to
> work with in consumers because they come at the end of the data so you have
> to do multiple passes or keep lots of data in memory, and I think you'd lose
> most of the distinctive renderings off the OSM map, though since that's such
> an opaque process it's hard to know.
>
> building=university would work, but only if done in a controlled way so that
> we don't break the map while it's being done. But do you really want to
> spend your days in front of a computer changing all the university tags in
> Cambridge though?! I can think of more productive and helpful things to do.
> I did consider building=university, but like all things OSM, there was a
> camp that only wanted building=yes, and that is what the Map_features page
> then decreed (it has more now, but university isn't among them). The more
> critical tags from my point of view are the operator ones.
>
> This raises some other points though...
>
> 1. What about the sites and the colleges? These are also tagged University,
> and there isn't an obvious alternative that won't mean the ordinary OSM maps
> don't show them. Fundamentally, is a "part of a university" a university? I
> think it's helpful to do it like that. Did you know the University of
> Nottingham has a branch in China - would it really be helpful to link these
> with relations spanning the world? I think there's cases both ways.
>
> 2. What is a University anyway? Almost no university is in one physical
> area. Even campus universities like UEA have outlying premises (in UEA's
> case in London too). Do you really not want the campus area to be tagged
> university just because it isn't the whole thing? You said Anglia Ruskin was
> one of the two universities in Cambridge - no it isn't, it's HALF a
> university, the rest is in Chelmsford. I don't think it would do any harm
> and would be helpful to group them with relations, if that were maintainable
> sustainably, but not at the expense of losing the tags from the outline
> itself. And the building thing only extends this further. Is a University a
> geographical thing at all? It's an institution, which may have some
> buildings but really it's a concept not a physical object - ultimately
> everything on the map is just a part, not the whole.
>
> 4. Constantly changing tags creates a moving target that is extremely hard
> to maintain for data consumers, and is a major off-putting factor in using
> OSM, especially if you can't manage the process because things just change
> under your feet. For example, there is a thread on talk discussing
> completely changing the amenities altogether, without regard for people who
> want to use this stuff in the real world. My view is that tags are merely
> tokens and too much is read into the words. They are part of the API and the
> fact you can change them because you prefer some other structure doesn't
> mean you should. The flexibility means we can introduce new things easily,
> but constant change is hard to cope with. The costs are borne elsewhere, and
> what really does it buy us?
>
> So, I think it's OK the way it is. If it offends you unbearably,
> building=university wouldn't be too hard to cope with, but please, please
> don't just do it, let me change the University software first, otherwise the
> map will be broken on next update (which are frequent) and they will be very
> annoyed. As I said, this is effectively part of the API, even though it may
> not feel like it, and constitutes a non-upward compatible change. If you do
> want to do it, please do it all, not in bits, and bear in mind this has a
> direct financial cost to me as a freelancer supporting the University map,
> and that the University has been a big benefactor for OSM, even though they
> get the rest of the map back in return, so you really don't want to give
> them a slap in the face for doing so.
>
> David
>
>
> On Thu, 21 May 2015 at 23:13 Phillip Barnett <phillip.p.barnett at gmail.com>
> wrote:
>>
>> I'm a Cambridge mapper, but I'd advise doing nothing until you've spoken
>> with David Earl who was contracted by Cambridge University to actually map
>> the university - see this link
>> http://soc2012.soc.org.uk/node/16.html
>> Thanks
>>
>>
>>
>> > On 21 May 2015, at 22:39, Dan S <danstowell+osm at gmail.com> wrote:
>> >
>> > Hi all,
>> >
>> > I don't relish bringing this up since it's a bit of a tangle, but I
>> > noticed Cambridge has a lot more universities than I thought!
>> > Apparently 1219, judging from the number of amenity=university tagged
>> > objects. In real life I'm aware of two: Cambridge Uni, Anglia Ruskin
>> > Uni.
>> >
>> > I think someone mentioned Cambridge Uni was using OpenStreetMap for
>> > some of its maps,* so I'd be nervous about proposing anything radical
>> > right now. But is there anyone on this list who is a Cambridge mapper,
>> > or connected to the university's use of mapping? It's possible that
>> > some team decided to use the tag to mark every college building (etc),
>> > when really amenity=university is supposed to mark a university, not a
>> > piece of a university.
>> >
>> > To do it "properly" it might need some neat relations to group these
>> > things. (Might be fun for someone who loves relations - various
>> > multi-site and hierarchical connections among the buildings scattered
>> > across town!) Alternatively there are tags in use such as
>> > building=university which might be good drop-in replacements...
>> >
>> > Best
>> > Dan
>> >
>> >
>> > * They use OSM for their basemap: http://map.cam.ac.uk/ - I wonder if
>> > they're getting their POI info from it too
>> >
>> > _______________________________________________
>> > Talk-GB mailing list
>> > Talk-GB at openstreetmap.org
>> > https://lists.openstreetmap.org/listinfo/talk-gb
>>
>> _______________________________________________
>> Talk-GB mailing list
>> Talk-GB at openstreetmap.org
>> https://lists.openstreetmap.org/listinfo/talk-gb



More information about the Talk-GB mailing list