Evening all, what going on with these crime maps then…

So initially the  moral of this story seems to be, if you are launching a Government website across the mass media, make sure you do the load testing with 100x what you expect.

The real issue is that despite having best intentions and a commitment to transparency, it’s very easy to confuse, mislead and lose credibility with poor crime mapping.

One of the  key positives of UK police website is the availability of the data behind the site which can been downloaded or accessed via a REST based API, secondly and something which few commentators have mentioned a link to local police teams who are ultimately responsible for reducing crime at the local level. Of course one years aggregated data is of little value here, allowing only relative comparisons between locations to be made, the real value will come in the future years when trends are identifiable and hopefully may be linked to local policing initiatives.

Many have commented however on issues with the mapping where the site designers have tried to offer more detail than the previous ward level statistics by moving to reporting the actual location of crimes, as commonly found in American crime maps.

While this is something I personally think should be made available, the map is not actually shown the real locations.

Many crimes are not accurately located in the first place, and because of privacy concerns expressed by the Information Commissioners’ Office some locations have been modified, moved or aggregated so that the points displayed on the map do not actually represent the actual location of the crimes but are indicative of the location.  I think it’s clear that perhaps an American style crime map was intended but what have ended up with is an uncomfortable and misleading compromise.

The fact that the points don’t actually represent the locations of crimes is at one level understandable, but to most people a point on the map represents the location of something, so much of the uproar in the press calling into question the accuracy of the maps can be understood.

However because the underlying data is available, budding data visualisation experts and cartographers can get to work and attempt to produce maps and other visualisations that perhaps better represent the data, already Jonathan Raper’s team at placr have come up with this different visualisation, using a multiresolution grid rather than the less obvious neighbour/street locations.

I hope the Home Office is not put off by the criticism of this first attempt, if Government is really to be more open and make use of the web in tackling complex issues such a crime and the local perception of crime, they must follow the web philosophy of constant iteration and development.

So they must dust themselves down, listen to the criticism, and make the next version better; and the following version even better… but quickly !

Written and submitted from the Google Offices, London (51.495N, 0.146W)

3 comments

  1. Ken Field

    Good post Ed. I had a bash at the mapping on the site myself (http://bcsmaps.blogspot.com/) but the wider points you make are important. It’s just a shame that so many of these so-called ‘official’ maps start life with such a poor design which hinders their utility & potentially causes more damage than good. I’ll let you know when the Home Office pick up the phone and ask for some carto design advice…or maybe it’ll be a loud knock at the door early one morning 🙂

  2. Malachi Rangecroft

    X does mark the spot, except you need to go to another site to see it.

    Have police.uk open in one tab and then visit http://www.beatcrime.info (a West Yorkshire Police mapping site that has been around for 5 years with dots on maps)

    Enter a location (e.g. LS11 8AR). Now select a similar zoom level for both, ensure the same crime type is selected – such as burglary – and then start to see the subtle differences.

    That’s because the WYP doesn’t snap to road segments and shows the crime as recorded by location. Police crime data can be notoriously difficult to geocode for non-postal addresses, such as much of the ASB that takes place, but a lot of effort has gone into improving the location accuracy by adding additional gazetteer data, such as points of interest.

    You might need to do the above quite quickly, as beatcrime is probably on it’s way out due to cost savings (why have 2 websites that do ‘similar’ things)? It’s ironic that the first police mapping site to show dots – accurately – has now been superseded by a national site that generalises the location.

    (..and a final point, beatcrime was developed internally for a relatively low cost).

  3. TimW

    This is another case that shows that a proper understanding of the data is key to making it work effectively. A similar thing applies to the MOT failure data the DVLA was forced to publish last year.

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