OpenStreetMap

Project Drake - mapping the University of Cambridge

Posted by davidearl on 5 December 2011 in English (English)

Cambridge University comprises around 200 faculty, departmental and related institutions on 10 or so sites (several of which are rabbit warrens of building over centuries) and distributed in and around the whole city of Cambridge. It shares a biomedical campus with Addenbrooke's Hospital currently expanding by 50% and most years see several new buildings erected and departments move premises.

The University manages over 700 properties. It has 31 independent colleges each of which occupies sometimes two or three sites around the city and a few of which are as large as an entire campus University. It has over 17,000 students and over 9,000 staff (not counting those employed by colleges) and innumerable visitors.

They all need to find their way around.

So, since September, on behalf of the University's Computing Service, I have been cycling and walking around all the University and College properties, measuring and photographing, and entering the data into OpenStreetMap with a view to potentially replacing the University's existing online ( http://www.cam.ac.uk/map/ ) and paper maps. This is code-named 'project Drake' and continues until June 2012. It is a feasibility study, but the hope is that it will be proved sufficiently feasible that it can become a live system.

Of course, quite a lot of the University is already in OSM. Some colleges are already mapped down to individual trees; others are just an outline of the perimeter. Some University sites were missing altogether; others had been traced from satellite with no additional information and had errors that you might expect when viewing entirely vertically.

The University of Oxford already uses OpenStreetMap in its OxPoints project ( http://www.oucs.ox.ac.uk/oxpoints/ ). However, it is not at nearly the same level of detail - it merely uses OSM Mapnik tiles for presentation (I think). Drake will tightly integrate the geography in the OSM database with the institutional information from the University, and it will have its own rendering. There should also be an API - though perhaps not quite to the extent of OxPoints which offers 10 different formats.

What Project Drake is doing on OSM is
* adding all the necessary missing detail
* creating consistency across the whole University estate
* checking accuracy
* recording entrances to buildings and sites (none I have done so far
have had this level of detail)
* assigning identifiers ('ref=...' and 'operator=...') to sites, colleges, buildings and entrances (using existing University sources where appropriate) so we can link the non-geographical data in University databases to the geography in OSM, and to highlight the necessary features on the map and website. These IDs will also form the basis for a URL addressing scheme into the University's online maps.

And then there is a sizeable software component for creating the map tiles in the style to which they are accustomed, index, paper map and web site.

We're not attempting to map inside buildings (though there are interesting edge cases where long, wide, geographically significant gateways, and colonnades well within building footprints, have building entrances inside them, which we need to be able to locate). However, we are mapping buildings and their surroundings at a level of detail greater than any street/POI mapping I have done before.

I've published the tagging schema I'm working to, here: http://wiki.openstreetmap.org/wiki/Cambridge/University_of_Cambridge

A couple of notable things to draw from it are:
* the University and the Colleges are private property, even though many of them allow tourists to visit at certain times. The paths through them aren't 'permissive' as had been widely tagged previously ('permissive' paths have formal agreements to allow general passage while not becoming rights of way; that's not the same thing at all, and the institutions are understandably sensitive about this).
* I'm naming buildings by their name. May seem obvious, but it has been common for buildings to be marked according to their occupier. It is very tempting to say this is the "Department of Psychology" rather than the "Sir William Hardy Building", but the latter is the correct name. Of course, I am also recording the occupier as well, both in the index that will drive the University map and in an OSM tag, just not the name tag.

GPS is not a particularly helpful tool at this level. Many of the central sites receive no appreciable GPS signal at all, and even where the signal is strong it is not accurate enough. Bing satellite imagery is exceptionally helpful, but it is easy to fall into the trap of thinking because it is a picture it cannot lie (and I've found many instances where this has happened). I will write a separate diary entry about this shortly ( http://www.openstreetmap.org/user/davidearl/diary/15400 ). The University's own material is often helpful (with permission, of course, and where it is not contaminated with OS copyright).

My main mapping tool though has been a 50m laser measure. I have a trolley on wheels on which I have mounted a white target, so I can measure building dimensions up to convex corners. Where buildings are generally orthogonal and orthogonal to each other, this gives very good results. Old buildings often aren't straight or aligned with each other, but even where a building is too new to appear on satellite, it is usually possible to locate it with reference to one that is.

To date, all the enclosed University sites except for West Cambridge and Addenbrooke's have had the Drake treatment, and eight of the 31 colleges - Clare College, Downing, Gonville & Caius, Hughes Hall, Magdalene, Pembroke, Selwyn and Wolfson.

Watch this space for more on this exciting project as it progresses.

Location: Newnham Ward, Cambridge, Cambridgeshire, East of England, England, United Kingdom

Comment from lyx on 5 December 2011 at 22:49

Having visited Cambridge I'ld say your project is really HUGE, and very cool! Looking forward to news from the project.

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Comment from Socks on 6 December 2011 at 12:09

For what it's worth, Oxpoints can store a reference to an OSM object - for example the "way/99933769" in http://data.ox.ac.uk/doc:oxpoints/40002001

However, this hasn't really been used, and due to the volatility of OSM objects (especially as stuff is being deleted and resurveyed for ODbL compatibility reasons) I guess there won't be much takeup of it anyway.

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Comment from Alexander Dutton on 6 December 2011 at 12:24

Hi David,

I'm the maintainer of OxPoints, and it's great to see you doing similar stuff. Here's a bit more about what we've been up to.

For OxPoints we've put together a CC0 set of entrance co-ordinates for buildings so that people can put things on maps without needing to worry about attribution. I've also started adding references to OSM features where possible (e.g. "way/12345"), so that it's possible to use the richer geospatial information in OSM in alongside all the other metadata we have. For example, http://data.ox.ac.uk/doc:oxpoints/40002001 contains both OxPoints data and data pulled from OSM, represented as WKT.

I've also started tracing buildings from Bing in OSM where they don't already exist (mostly some Worcester and Magdalen College buildings, and the University Science Area). By using the links to occupants in OxPoints, we can do cool stuff like http://data.ox.ac.uk/explore/science-area/.

(One of the factors in making this possible is our use of RDF and linked data. We've got stable URIs for each place and organisation part, and we can record arbitrary relationships between them. Using RDF means make it easy to preserve the semantics of each bit of information, which in turn makes it easy to add new serializations.)

If you're interested, there're some other people that are modelling and recording this kind of organisational and building information that hang out on the buildingdata list (http://mailman.ecs.soton.ac.uk/mailman/listinfo/buildingdata).

Good luck with your mapping! By the looks of it your tagging schema would be of particular use in recording the vagaries of some of our places (quads and staircases still don't fit into our model very well). I'll keep watching with interest.

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Comment from davidearl on 6 December 2011 at 19:32

Thanks for that Alexander - I'll contact you directly so we can keep in touch more directly than via diary pages!

The volatility issue is why I chose to include explicit reference IDs to identify buildings, sites and entrances (and it is also the recommended method). And it helps that the University has a ID scheme for sites and buildings already to draw on (I have in effect extended that to the colleges).

The IDs and URIs will be equivalent, so they function just like yours, and like you I expect to be able to produce site maps like your science-area one. I'm not planning on using RDF though, merely linked tables within a conventional database.

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