• OS releases OpenSpace API

    Dec 18, 2007

    I was invited to attend a private “hack day” at the offices of the Ordnance Survey on Friday last week for the launch of their new OpenSpace API. A number of other people from the Open Street Map community were also invited (leading to talk of attempts to extinguish the OSM project by doing away with us all!)

    An OS Surveyor and an OSM SurveyorIn actuality the guys at the OS were really friendly and had a day of activity planned for us. After the initial introductions we were split into two groups and went off for a mini-tour of how they collect their map data. My group first got to head outside and talk to one of the few hundred on-the-ground surveyors that the OS have. He showed us his collection of equipment, from the low-tech popeye to the 2 metre GPS mast, back-pack full of GPS equipment and the tablet PC for entering new data directly. It was really interesting to listen to his experiences of surveying and to compare it to my own. I’m not sure that he realised that most of those present would consider themselves to be “surveyors”, I’m sure he’d laugh if he heard it though considering the accuracy and quantity of the data that he would collect in an area would be far more than that taken by most OSM mappers.

    After this we were taken off to the Photogrammetry department to find out about how OS are using aerial imagery for mapping. OS run two planes, one flying with a traditional film camera and one with a digital camera, to collect their own imagery of the country. They make sure that the imagery they collect overlaps and then use all sorts of advanced processes to convert this into a 3D model - processes such as wearing funny glasses while staring at a screen and clicking the imagery when features overlap. We saw some incredibly detailed imagery - yes, better than google maps - but unfortunately I didn’t get to see their imagery over my house and find my car.

    After this mini-tour we were then given a longer introduction to the OpenSpace project itself, their reasons for launching it (a combination of “we want to” and “we had to”) and the terms and conditions of use, which unfortunately turned into an hour long discussion that nearly scuppered lunch! The terms that OS are using have various provisions for deriving data from the maps (which suggested a npemap.org.uk type postcode collector might be allowed) but also don’t allow for commercial usage. After we did finally have lunch we all signed up for the API and started hacking. Here’s what I ended up with, a low resolution plot of my route from London to Southampton:

    Click for bigger

    The API itself is built on top of the existing OpenLayers API. I think this was a really good decision by the OpenSpace team as the world really doesn’t need yet another JS slippy map implementation, and to have a large company developing with OpenLayers, can only help to improve that project. Rather than going with a WGS84 based system though, OpenSpace centres around the use of BNG (British National Grid). Though in theory this is an obvious choice for OS, considering that BNG is “their” system and is the system in which all of their raster based mapping is available (I think), the fact that they require coordinates to be entered using BNG by default is definitely going to lower the number of people that bother to use it.

    Though a conversion system is provided by the API, I was interested to find that they are using the algorithmic method to convert BNG eastings and northings to WGS84 latitudes and longitudes, rather than the full National Grid Transformation OSTN02. I’ve never been too sure of the difference in accuracy between these and looking at the page on wikipedia about BNG I find it’s about 7m accuracy for the Helmert datum transformation which I assume they’re using. I guess that’s fine in most cases but Multimap does have a free web service available for doing the more accurate translation, get in touch with me if you want more information :-)

    When trying to put together the small implementation you can see above I also came across a few problems that also seemed to arise from the use of BNG. To give you a quick pseudocode run-down, my app basically does the following:

    • Setup data

    • On page load

      • Create new map object

      • Create GridProjection object for converting eastings/northings to lat/lon

      • Create Vector layer for drawing the line between points

      • Loop over the points for my route from London to Southampton

        • Convert position to BNG

        • Create marker at the point

        • Add the point to an array, for drawing the vector later

        • Extend a bounds object to contain the complete bounding box of the journey

      • Draw vector

      • Get centre of the journey’s bounding box, and the zoom factor to fully display it

      • Display the map of the journey.

    I came across a number of problems when I tried passing my converted points into the OpenLayers.Bounds object and an array of the points into my vector. After playing around with it for a while I’d managed to get my markers to display, but not the vector, and the map wasn’t properly autoscaled to my journey. After looking at the vector example though I noticed that they were passing OpenLayers.Geometry.Point objects into the vector, and OpenSpace.MapPoint objects into the setCenter method. This is quite possibly a problem with OpenLayers rather than with the OpenSpace implementation, though I can’t be sure either way. After a little playing around though I found that adding the following line of code, then using the point variable with the bounds and vector objects fixed my problems:

    point = new OpenLayers.Geometry.Point( mppoint.lon, mppoint.lat );

    So, conclusions: I have to say that I don’t think that this API is ever going to change the world. There are so many mapping APIs out there that are freely available anyway that this one is just not going to have that effect (especially with Multimap offering the same landranger 1:50k data, in a WGS84 environment). That said though, I can see definite uses for it in the UK, and I know that many UK based organisations will be happy to use the BNG system. It also means that Ordnance Survey are going to be meeting their mandate to promote the use of their data and noone can say anymore that there’s no way to get access to Ordnance Survey data free of charge (or at least when the API is available outside the current closed release anyway). There may be lots of restrictions on use at the moment, but at least it’s something and hopefully this small step will lead onto a lot more open-ness at the OS. Also I definitely don’t want to put down the guys that have been working on this, what they’ve achieved is great, they just need to keep working on it, and working on the people above them to allow more data and more freedom of use for the data.

  • Simple Static Maps API, similar to Google Charts

    Dec 11, 2007

    I’ve been subscribed to the 24 ways feed again this year. They’ve had some really interesting stuff I might make use of sometime such as the Javascript Internationalisation and Neverending Background Image articles. Today’s article on the new Google Charts API reminded me of something I thought of last week when the Charts API launched. Multimap have recently launched a new way of accessing their maps API which I think is actually pretty similar to the Google Charts API in some ways. The new static maps API is an incredibly simple way to insert a map onto your pages without having to write any actual code, it allows you to put maps on pages that you don’t expect your users to hang around on for long and they’re great for using with mobile devices.

    The Multimap Static Maps API is similar to the Charts API because to get a map all you need to do is put some parameters on a URL, you can get a map with a single qs=[postcode] parameter. A big difference is that you do have to sign up for an API key. This isn’t too difficult though, you’ll need to register for “My Multimap” then head over to the Open API Signup page to get your key. Once you’ve done that you can use this key to access the JavaScript API as well as the new Static API. You also must provide a link on your page to the terms of use.

    So, let’s get cracking shall we? Here’s a map featuring Multimap’s office on Fleet Street in London, the postcode for it is EC4A 2DY so I’ll just use that:

    http://developer.multimap.com/API/map/1.2/[api_key]?qs=EC4A+2DY

    Map of Multimap's Office

    Terms of use

    If I’m going to give you lots of examples, I should probably trim that image down a bit, maybe make it a bit wider, but shorter. I think I’ll also change the label on the marker, in fact I’ll just get rid of it for now, how does this look?

    http://developer.multimap.com/API/map/1.2/[api_key]?qs=EC4A+2DY&width;=450&height;=300&label;=+

    Map of Multimap's Office

    Terms of use

    When passing in geocode search parameters or marker labels be sure to URL encode the strings, the Javascript function encodeURIComponent is good for that. Also note that I passed a single space into my marker to give it a blank label.

    I think it would be good to display some landmarks on the map too so that you have an idea of whereabouts Fleet Street is in relation to, say, Saint Paul’s cathedral, Buckingham Palace, The Houses of Parliament and the London Eye, so how’s this:

    http://developer.multimap.com/API/map/1.2/[api_key]?width=450&height;=300&labels;=+,1,2⪫_1=51.51428&lon;_1=-0.10823⪫_2=51.51373&lon;_2=-0.09901⪫_3=51.50182&lon;_3=-0.14061⪫_4=51.49917&lon;_4=-0.125⪫_5=51.50383&lon;_5=-0.11972

    Map of Multimap's Office

    Terms of use

    1. Multimap’s Office, Fleet Street

    2. Saint Paul’s Cathedral

    3. Buckingham Palace

    4. Houses of Parliament

    5. London Eye

    This is all very UK-centric though and it would be a shame to ignore the great mapping that Multimap provides around the world, so how about we do a bit of shopping in New York? We’ll hit a few of the big shops first then head somewhere a little more affordable to get a few things for ourselves:

    http://developer.multimap.com/API/map/1.2/[api_key]?width=450&height;=300⪫_1=40.74982&lon;_1=-73.98954⪫_2=40.76221&lon;_2=-73.96821⪫_3=40.76266&lon;_3=-73.97395⪫_4=40.74225&lon;_4=-74.00426⪫_5=40.73986&lon;_5=-73.99497

    Shopping in NY

    Terms of use

    1. Macy*s Department Store

    2. Bloomingdales

    3. Tiffany

    4. The new Apple Store

    5. Old Navy

    And finally to get things even more international how about all the places I’m lucky enough to have travelled to this year (largely due to weddings/honeymoon):

    http://developer.multimap.com/API/map/1.2/[api_key]?width=450&height;=300&qs;_1=Liverpool⪫_1=53.41667&lon;_1=-3⪫_2=9.4759&lon;_2=99.9566⪫_3=22.32341&lon;_3=114.21175⪫_4=39.9045&lon;_4=116.391⪫_5=36.71963&lon;_5=-4.41991⪫_6=41.066&lon;_6=29.0061

    Places I've been - 2007

    Terms of use

    These are just some of the things you can do with the static maps module, take a look at the full documentation for more examples. I’m hoping that we’ll get quite a few people using this, it’s a really good way of getting a map onto a page without requiring the larger payload of a full JS API. If you do make something then why not put a comment on this page, maybe you could do a map of all the places you’ve been in 2007?

    Technorati tags: staticmap, charts, google, multimap, map, api

  • Visiting Yahoo!

    Dec 11, 2007

    I paid a visit to the Yahoo! offices in London last week, having been invited to a “Yahoo! Developer Summit”. I was intrigued to find out what was going to happen at this “summit”, especially with 3 days allocated for it. I had assumed it was going to basically be a mini-conference with a mix of Yahoo! employees and outsiders attending. As it turned out it was basically an internal Yahoo! event with talks covering various topics, generally “web dev” related, to which a small number of external people had been invited.

    Unfortunately, being pretty busy in work I was only able to attend on the Wednesday and some of Friday, but I still got to see a good range of talks. In fact the range of topics was pretty broad and not particularly Yahoo!-centric at all. I attended talks on “web security and XSS”, “High Performance Web Sites”, “Using Bazaar for Version Control”, “Working in Distributed Teams” and “Writing Engaging Tutorials”. There was also a great keynote from Simon Willison on using comet server push technologies, something I’m definitely going to use in the future.

    I also have to mention the pub quiz that ended the summit. As Jeremy has mentioned we outsiders banded together to fight off the Yahoo! hordes. Apart from my absolute insistence that Firefox 1.0 was released on 19th December 2003 (I was thinking of the date of the New York Times advert, but got it wrong by 3 days and 1 year and the release actually occurred a month before anyway!) we still did pretty well coming in third, as Norm had said from the start “if you win, that means you’re the biggest geeks” so I’m glad to say our coolness held us back from that first place spot. I still got to choose a selection of Yahoo! merchandise to take home from which I took a delightful YDN t-shirt and an “Insta-Yodel!” (which I donated to SteveC at the OSM xmas party and he had lots of fun with).

    So all-in-all I have to say I enjoyed the event, it was a shame I couldn’t make it to the whole thing, but 3 days was just too long to be out of the office (especially when Internets were in short supply at Yahoo!) I’d happily go along if invited again, hopefully Yahoo! will open it out to more people in the future too. Talking to some of the Yahoos there did seem to be a feeling that they should be doing more in the general community. I know that we at Multimap also want to get more involved in the web dev and mapping communities more in the future too so perhaps we can find a way to arrange a combined event in the future.

  • First Liverpool Mapping Party a Success

    Nov 13, 2007

    We held the first Liverpool mapping party over the weekend and I’m glad to say it went pretty well. Though we didn’t get as many new people turning up as we would have liked, we still managed to cover quite a lot of ground. Our main target for the weekend was to get as much of the centre of Liverpool mapped and it looks like we managed to achieve that aim. There’s still a few areas towards the North West that need finishing off, and the Paradise Street Project still needs to be marked as “under construction” somehow, but we’re basically there for central Liverpool as you can see from this animation:

    Central Liverpool Animation

    CC-BY-SA Some rights reserved.

    We also had people out mapping in other areas of Merseyside, Crosby got it’s first detailed OSM coverage, as did Birkenhead and Everton. Aigburth also saw numerous improvements including some path mapping in Sefton Park.

    I have to say a big thank you to the guys at Glow New Media for their support, not only did they let us use their office as a base for most of Saturday, but they also provided breakfast and lunch! We also have to thank Rightmove for providing drinks and food in the evening.

    We’re already planning the next party which we’re hoping to hold in January 2008. We should be able to get a dedicated space to use for the party to allow people to come and go more freely, and we’ll be advertising this one a lot more to try to get new people involved. I’m sure I’ll be blogging about it as soon as I have more information about that.

    I’ll finish off by thanking everybody who came, it was great to see some people who hadn’t mapped at all before, and it was good to have lots of established mappers in attendance to help them out. I know some people travelled a long way just to help us out in Liverpool which is really appreciated. So, finally, the obligatory image showing all of our traces:

    Click on image to see key

    Liverpool Mapping Party Traces

    Technorati tags: liverpool, liverpool0711, osm, openstreetmap, map, maps

  • Recent Mapping Activities

    Oct 12, 2007

    I thought it was about time I mentioned mapping in my blog again. I’ll start by mentioning a recent development with the Multimap Open API. Expanded UK data coverage is now available which should enable a lot more interesting UK mashups. The article mentions in more detail what is now available but basically you can use Ordnance Survey Landranger maps together with full UK postcode lookups. I’m really hoping that this will get people excited enough to knock up some cool demos. The blog posting over on blog.multimap.com shows an example plotting a trace from when I took five multimappers off walking in the hills of Wales, but I’m sure there’s a lot more that can be done (geocachers are you listening?)

    My second link is actually about something that Microsoft have done using the traffic logs from their Virtual Earth (Live Maps) traffic logs. It’s been a few weeks since the link was posted but I wanted to also link to a similar thing that was done using Open Street Map traffic data. You can also view stats on the 10 most popular tiles from the innovative “Tiles@home” project (scroll down the page, or search for “Popular areas”).

    Arbitrary Map of Liverpool, see below for explanation

    Liverpool John Lennon Airport and Speke Housing Estate

    CC-BY-SA Some rights reserved.

    Finally I should mention that I’m organising an Open Street Map mapping party in Liverpool in a few weeks time. Venue is yet to be confirmed but the date has been set to the 10th and 11th November (2007). You can visit the OSM wiki page for Liverpool or the event page on upcoming.org for more information. Liverpool’s coming along really well but there’s still plenty more to be done, hope to see you there!

    Technorati tags: osm, openstreetmap, maps, mapping, liverpool, merseyside, ordnancesurvey

  • Wedding and Honeymoon Over, Married Life Begins

    Sep 27, 2007

    Forbidden Palace, Beijing After taking numerous attempts to write this blog post and going into far too much detail I’ve decided to trim it down to a few paragraphs, I’ve got a few other ideas for posts but really should get this one out first!

    First, the wedding. The day went really well and surprisingly smoothly. Everybody that we’d picked to help us out with our wedding was brilliant and helpful. About the biggest problem was the DJ (hired via an agency) but then it’s no big surprise to hear of a wedding DJ playing crap music. Apart from this the day was amazing, it was just great to be able to get all of our friends and family together and have a big party. It’s also great these days that with the wonders of modern technology we managed to see lots of photos taken on the day before we even went on honeymoon!

    Wild Goose Pagoda, Xian Secondly, the honeymoon. We spent an amazing three weeks touring around China (Beijing, Xian, Guilin), visiting Hong Kong, and lazing on a beach in Koh Samui, Thailand. The culture and heritage in China was incredible, and our guides were really good at telling us all about it. Hong Kong was smoggy and cold (air conditioning!) but still an interesting place to visit. Finally Koh Samui was just a really nice place to relax for a week.

    We travelled on 9 flights on our trip (going to and from the far east via Dubai) and apparently used 7 tonnes of CO2 to do it. Fortunately that’ll only cost us about £50 to offset apparently so we’ll probably do that soon. We used 4 currencies and needed 3 visas but it was all worth it for the great time we had, evident in the 830 photos that I took (select few now showing on flickr!)

    So, I’ve kept this short, but if you’re interested in hearing more about the honeymoon then just drop me a line or ask me when you next see me. I’ll end this blog post in the only way appropriate by saying: my wife and I thank all of our friends for helping us make our wedding day go so smoothly and for helping us have such a great time.

    Technorati tags: wedding, honeymoon

  • Wedding Day Imminent

    Aug 24, 2007

    As usual I haven’t really been blogging much recently, and when I do it’s usually about some tech subject or other. Something that’s not particularly techy, but a pretty big event for me, will be occurring tomorrow though and I thought I really should put some mention of it up here. I’m getting married!

    Pretty much everything is arranged now, though there’s still lots of jobs to get done today and tomorrow morning to make sure everything runs smoothly. As you may have seen from my twitter stream, we got the rings and the rest of the suits yesterday. Today we need to do some last bits of shopping for our honeymoon, we thought some new luggage might be useful, and then I need to start transporting stuff over to the hotel that we’re holding the event in. My fiancé obviously has all sorts of girly jobs to do, such as picking up dresses and getting her nails done and getting all her family together in our house.

    In good tradition, I’m spending the night elsewhere - I have a lonely little single room in the hotel to keep me company. Fortunately half the wedding guests will be staying there too so it shouldn’t be too bad :-) Tomorrow there’ll be lots more jobs, making sure the hotel is all ready for us, and distributing the corsages. I’ll probably end up having to make sure everyone has transport to make it to the church and back too, but that shouldn’t be a big problem as there’ll be lots of cars around. After that there’s something about standing in front of a crowd of people and saying something along the lines of “I promise to give you all my money”, or something along those lines…

    Well, my fiancé’s calling so I think I have some jobs to do. I’ll probably update my twitter feed if you’re interested in what’s going on, hmm.. and sometime I’ll start my speech.

  • State of the Map? Pretty damn good

    Jul 16, 2007

    I spent the weekend at the State of the Map conference in Manchester. This was the first annual conference for the Open Street Map project and featured a weekend of talks all about maps and geodata.

    I have to say I really enjoyed the weekend. I’ve been to a few conferences in the past few years (though only a few) and I have to say I probably enjoyed this one more than any of the others. A lot was packed into the weekend - there were 22 talks scheduled to last between 15 and 30 minutes, and then there was lots of “lightening” 5 minute talks too. I think what made the talks so good was that, for the most part, they were given by people who were heavily involved in the project and had a real passion for what they were talking about.

    A lot was said about the value of good cartography. Richard Fairhurst began this by outlining some of the benefits of good cartography (essentially getting a useful amount of information onto the map in a clear way) and it was followed later by Steve Chilton telling us some of the basic principles of cartography that may be getting ignored by us mapping newbies. The legal debate gave me some definite food for thought, unfortunately nothing was resolved (in my mind, let alone within the community) but it definitely helped to talk through some of the issues. There was also lots of talk about tagging, about definitions of “complete” and about making use of our maps on various devices too.

    I definitely can’t go without mentioning Barry Crabtree’s talk on “Bringing Maps to Life”. Barry showed us a number of animations that he’d done using OSM data. Generally these involved vibrating nodes to make the maps move in various ways. Although it doesn’t initially sound of a huge amount of use, and many of his animations were essentially frivolous, it’s research like this that can highlight new and innovative ways of doing things. A very important point that he did make at the end was that none of his animations would have been possible without OSM. The only other way to do it would be to pay huge amounts for commercial data, it’s highly unlikely that anyone would do this in the name of “art”. Fortunately I have links to a few of his animations, take a look at the route animation, the beating heart of ipswich and the hypnotic squirming roads.

    So all in all I think a great weekend was had by everyone, I was definitely inspired by much of what I saw. At times I felt I wanted to get my laptop out and write some code, but knew I’d miss things if I did that (and the wifi didn’t stretch to the lecture theatre anyway but that wasn’t much of a problem). I think the best way to finish this blog post is with a link to flickr for the group photo.

    Technorati tags: osm, openstreetmap, multimap, events, sotm, sotm07, mapping, map, art, cartography

  • What my friends did at Hack Day

    Jun 21, 2007

    I went to the event with a number of other multimappers who all got down to hacking fairly sharpish...

    So now that my friends have all got stuff online I can finally blog about what they got up to…

    Firstly is Richard Rutter and Andy Hume, they knocked up a prototype of a really handy app that helps people to arrange an event. One person can setup a “potential” event (e.g. “John’s Stag Do”), they can then enter a number of possible dates, and a number of venues. They then invite all of the attendees to go in and select their preferred choice of date/venue and the dates/venues that they really don’t like. It’s a great little idea and was well put together and Rich did a good presentation in the 90 seconds he had. It was so good in fact that they won the “Most Useful Hack” prize! Take a look at Rich’s blog posting about it here.

    Second is Colm McMullan and Richard Keen. They extended an existing Multimap project that they’ve been working on for the past few weeks. They’ve built a Twitter bot that you can send direct messages to and it will reply with directions between two points, a link to a map, or even directions to local points of interest. They spent hack day adding support for the new FireEagle API from Yahoo! and put together a great video to demo it. The video is a spoof of the iPhone advert using the Multimap Twitter Bot to get directions to the nearest cinema and “seafood”. Link to the video coming up, but you’ll want to either take a look at the Multimap blog posting about the Twitter bot or head straight over here to the documentation.

    Ok, now you get to take a look at the video. The youtube version has lost a bit of quality in the conversion so a link to the original higher quality version follows it (26Mb download):

    Full version - 26Mb download

    Oh yes, and a few final thoughts. It’s not mentioned on the documentation page yet but there’s experimental support for Open Street Map data in the Twitter bot, just ask for your nearest postbox, supermarket, recycling, telephone, toilets, or even your nearest peak! I got the following earlier so looks like I’ll need to keep my legs crossed while I drive over!

    Directions from l19 to closest (the closest toilet) :: M62 > M6 > A534 (Old Mill Road)

    Lastly, in my previous blog posting I asked whether anyone was interested in logging their position by DNS, a few people said they would be so I’m going to look into doing something with this soon, keep your eye on my blog for more information…

    Technorati tags: iphone, hackdaylondon, multimap, events, twitter, upcoming

  • What I did at Hack Day

    Jun 17, 2007

    Got back from hack day a few hours ago (yes I left before the Rumble Strips played, was really tired for some reason even though I’d had a full night’s sleep last night). It was an interesting event, my favourite presentation being “New Geo Services from Yahoo!” presented by Mor Naaman and Tom Coates. They announced a new project from Yahoo! Research called FireEagle. The idea behind it is basically to have a centralised place for storing your current location, and offer an API so that third party services can update or read your location. It’s a great idea, allowing a single API to work with when doing “I’m here!” type apps, and one I’d actually been considering knocking up myself.

    I went to the event with a number of other multimappers who all got down to hacking fairly sharpish. I on the other hand just couldn’t think of anything to do, I wasn’t needed on either of their projects and just ended up doing some other coding I’d been meaning to do for a while to help out a friend. While doing this though I was still thinking about FireEagle and about whether there might be something related to that which I could knock up. After going back into London and getting a nice long sleep I went back over to Alexandra Palace this morning and decided that I would knock up a few things to update my location on FireEagle.

    The first of these is actually an extension of an existing PHP script that I already had. For a year now I’ve been logging my current location while out and about by using a bluetooth GPS and MobiTrack Pro java software on my mobile phone logging to a PHP script running on my web server. Modifying that script to update my location on FireEagle actually turned out to be ridiculously easy. The biggest problem was getting GPRS turned on for my new mobile phone!

    The second thing I knocked up was a way to update my position via DNS. While this may sound like an odd thing to do it’s actually quite useful. Often when you’re connected to a pay-for WiFi service you’ll find that accessing web pages when you haven’t paid for access will take you to an “enter your username and password here and/or pay us some money” page. Usually when this happens though you’ll find that you actually have full access to make DNS queries. Considering that GPS data is essentially just two numbers I thought it would be pretty handy to knock up a DNS server that accepted these two numbers and sent them over to FireEagle, and so that’s what I did.

    Fortunately it turned out to be quite simple as I already had an existing perl nameserver script that I could extend, 50 lines of code later and I had a daemon running on one of my server to which I can send lookup requests for hosts like this:

    l51d59296.l-0d13174.temppublic.15.nmea.a.example.com

    Which results in my location being updated (to Alexandra Palace in this example). It’s actually a fairly simple sequence, the parameters are as follows:

    ....nmea.a.example.com Latitude and longitude are prefixed by the letter "l" simply to make sure there's no hyphen at the beginning (as there would be for negative lat/lon), and the decimal point is replaced by the letter "d". The "user key" is simply looked up in a text file to get the user's application token from FireEagle and the counter just makes sure the DNS record is never cached. So I'm quite tempted now to knock these into some sort of service that anyone can sign up for but I'm doubtful of whether there's much demand. If you think you would use either service then let me know in the comments. Technorati tags: [GPS](http://technorati.com/tag/GPS), [hackdaylondon](http://technorati.com/tag/hackdaylondon), [dns](http://technorati.com/tag/dns)

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