Ordnance Survey National Grid Bing Maps App

Online web-mapping is a competitive business. There are Bing Maps, Google Maps, Yahoo Maps, Open Street Map, and many other providers. Until recently, Multimap.com was a popular mapping site here in the UK, partly because it presented Ordnance Survey maps and displayed OS grid coordinates under the map.

Like many countries that have their own national grid reference system, OS national grid coordinates are the standard coordinates used for mapping in the UK – they are also the format used for almost all data available from the British Government and other national agencies. When multimap.com was taken over by Bing, there was some concern voiced by users that the OS national grid coordinates were no longer displayed, replaced by the global hegemony of WGS84 latitude/longitude coordinates.

So, I took it upon myself to add back in the ability to display OSGB grid coordinates to Bing Maps, and creating a Bing Maps App seemed an ideal platform to do this.

Bing Maps Apps are Silverlight “plugins” that are published to and hosted on the www.bing.com/maps/explore site. A Bing Maps app typically overlays additional information (pushpins, polylines, or polygons) on the bing.com map representing a particular set of data, but it can also be used to add additional functionality to the map.

Gathering requirements for the app was easy – there were enough users bemoaning the loss of previous multimap features (“Why can’t we do xxx anymore?”) to work out what it had to do, and the calculations required to convert from latitude/longitude to grid reference are contained in a PDF document available from the Ordnance Survey website.

The coding experience itself was…. interesting. Writing Bing Maps Apps requires learning yet another SDK (which you download from the MS Connect site) separate from all the other existing Bing Maps family of products (e.g. the AJAX control, Silverlight, Windows Phone 7, SOAP and REST services). Many of these have similar features, namespaces, and classes, but they all differ slightly, and there were some head-banging moments when I tried to do things the way I was used to, rather than the “Bing Maps App”-way. Also, since Bing Maps Apps are plugins to an existing map (the one displayed at www.bing.com/maps), you don’t have to (and in fact, can’t) edit many of the properties of the underlying base map – only those defined in the layer used by your app itself. Again, I’m used to having full control over the page/app in which my map is displayed.

Some parts of development proved to be pleasantly simple, however. The debugging and testing from within Visual Studio, for example, was brilliant. And the deployment process was equally smooth – compile your app and upload it to http://www.bingmapsportal.com . You get an instant response from an automated test of your code, and then within about a week your app is published on the bing.com site – that’s it!

Here’s my OS National Grid app listed on www.bing.com: image

And here’s the app in action – displaying the OS Grid Square references at various resolutions for the current centre point of the map, together with the OSGB36 Latitude/Longitude:image

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11 Responses to Ordnance Survey National Grid Bing Maps App

  1. Rob says:


    I was interested in using your OS National Grid app. When I try to open it on Bing Maps, I get a message which says: “Map apps are not available in your market right now. We’re sorry for the inconvenience”. Does this mean that an application that is most useful to UK users is not available in the UK market? Or, have I mis-understood?



  2. Rob says:

    Many thanks – the direct link works

  3. Neil Jones says:

    they are still having the same problem….but the direct link works fine…!!!!

  4. Dan Piercey says:

    Hi Alastair
    Great App! – have been using it regularly to plan walking trips.
    As of yesturday when I zoom in, the 1:25000 scale OS map is no longer presented. Do you happen to know if this is a permanent policy change for Bing maps?
    I wonder if there is still a way to access the 1:25000 scale?

  5. alastaira says:

    Well damn it just took me a long time to find my own app! No idea what Microsoft are doing with Bing Maps Apps, but I had to get to the extremely well-hidden http://www.bing.com/maps/?appid=0 just now to get the list of apps up (www.bing.com/maps/explore doesn’t work any more)

  6. david seed says:

    well that ( http://www.bing.com/maps/?appid=0) at least gives an option to look at loaded apps, which the link in the body of the piece does not.


    But still it doesn’t list your app, perhaps you need to upload it again

  7. david seed says:

    your link to the OS pdf is wrong

    this is what you have

    this is what it should be

    at least until they change it again

  8. Susan Johnson says:

    Oh dear… I keep loosing what used to be the ordinance survey maps at multimaps…does anyone have a link to get there?? I am so tired of clicking links I am giving up for today.. OS National Grid what great maps!!! Just love them!!

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