Geo Stuff

I’ve just launched an awesome new iPhone app – Basic Sat Nav. A PND/Satnav app for your iPhone that will direct you anywhere in the world. Using Cloudmade’s great geocoding service I can provide essentially global coverage that no other iPhone satnav offers. Okay it doesn’t have advanced features like “Augmented Reality”. In fact it doesn’t have any of the more basic features like “turn by turn directions” but I think there’s nothing better than a series of textual updates telling you whether you’re getting “Hotter” or “Colder” for getting you where you need to be.

Basic Sat Nav "Hotter" ScreenshotOk, so maybe it’s a bit of a joke but I’ve been amused that everyone who’s seen it has paused for a moment and then said “cool! that would be useful for X“. The most obvious thing that people have asked for is Geocaching support so I may try to add searching for geocaches in the future, I’ll see how things go though as I really want to avoid feature bloat.

Testing a satnav really isn’t the simplest thing to do though. When testing iPhone apps in the iPhone SDK provided iPhone Simulator you get a single location update that puts you in Cupertino. This is obviously completely useless when writing a satnav. To get around this I wrote a new LocationManagerSimulator class that I could add to my project which will take in a Property List file (converted from a GPX file recorded earlier) and will replay the locations in that file every time I start the app. This was a really good way of testing things — so long as I had a well defined route in my GPX file I could then search for a location along that route and the sat nav would update as my recorded position got closer and closer to the destination. If I picked a location halfway along that route I could see the satnav updating as I got further from the destination too.

The simulator will take the HDOP and VDOP values from within the GPX file and will, using a simple metric (× 6) convert these to horizontalAccuracy and verticalAccuracy values. If they’re not present it uses fixed values of 50.0m for these fields. If there’s an “ele” field in the GPX then this will be used for the altitude, otherwise altitude is set to 0m. Currently the code is pretty basic but it does all that I needed it to and should be quite easy for others to use. Simply drop the two files (LocationManagerSimulator.h and LocationManager.m) into your project and change your reference to CLLocationManager to LocationManagerSimulator. If you have a file named simulated-locations.plist in your project then it’ll read from that by default. Otherwise you’ll want to use the full initWithFilename:andMultiplier: call, this also allows you to pass a multiplier so that the route runs faster or slower. Simulate a driving route on your bike or vice versa!

I want people to just go ahead and use this so I’m putting it out there as public domain/CC0 or whatever you need to be able to use it without worrying 🙂 You can download LocationManagerSimulator from github where you’ll also find a bit more documentation. If you feel guilty about using my code for free then please do buy Basic Sat Nav from iTunes. If you have ideas for improvements then let me know or, better still, fork the project and add them yourself!

Oh, nearly forgot to say, if anyone wants to try Basic Sat Nav out for free then I’ll give promo codes away to the first 20 people that ask in the comments. Unfortunately promo codes can only be used in the US iTunes store though so only ask if you’ll be able to use it!


So one of the great events that I’ve, er.. delayed writing about was the annual OpenStreetMap conference “State of the Map”. This year it was a 3 day conference (previous years had been 2 days) with the extra day accommodating the various commercial people that have started making use of OSM data. It was a great idea to bring in some fresh faces to the conference and actually gave me my first speaking opportunity of the weekend, talking for five minutes about The following two days took a more traditional course with various members of the community talking about the ways in which they are using and working with the OSM data.

A selection of countries gave a “State of <country>” type talk, these are always really great to hear, especially for the smaller countries where perhaps Internet access or access to GPS technology is not so great. Often in these locations there isn’t even any existing map data so there’s a great opportunity for the OSM community. The talks from Pakistan and Brazil were particularly memorable and were only made possible due to the great OpenStreetMap Foundation “scholarships” program which was a great way to make sure we had attendees from all areas of the world. It was also good to see these attendees being handed GPS devices as part of the GPStogo program which hopefully they’ll take home and use to collect many more GPS traces.

The OSMF Scholarship attendees

The conference took place this year in Amsterdam and it was my first time visiting the city, though I didn’t see much of it in the first few days while at the conference we fortunately stayed on (we being my wife and I) to spend another few days in the city for some rest and relaxation. We had a great time there and I had plenty of opportunities to use my (still relatively new at the time) DSLR camera as you should be able to see from the photos scattered around this post.


I managed to make it three years running speaking at a SOTM conference not only with my 5 minute segment about but also with a full half hour on Saturday afternoon talking about OpenStreetView. This is my idea for a project to try to create an openly licensed database of street-level imagery, and ideally some really impressive software to go with it. The talk went well though I had an “interesting” Q&A session afterward, obviously people are still concerned about the privacy aspect even when related to what I hope will become a very open project. Unfortunately at the time I hadn’t completed the software side enough to launch the project, and as you may have noticed I haven’t yet launched it, more on that soon.

Woman with child on bike

Next week I’ll be attending another conference, and again will be speaking about OpenStreetView. Ed Parsons has written about the conference that he “was disappointed with the introspection and backwards thinking demonstrated … and had all but given up attending” which doesn’t sound like a big vote of confidence. The conference is AGI Geocommunity and fortunately a big effort has been made by Stephen Feldman, Chris Osbourne, John Fagan, Rollo Home and many others to improve the situation leading to a really great and interesting looking programme.


As mentioned I’ll be speaking about OpenStreetView again, but this time I’m intending to have something launched and usable beforehand. It won’t be particularly pretty, it won’t have a huge number of features, and it probably won’t have a huge database of images, but I’m hoping this will all change once I open it out and get more people involved. My aim with the project is to build a database of images and metadata which can be built upon by others who are already working on the software side for viewing these things. It should also provide a home for imagery being created by various people who are already building hardware solutions for collecting it. Unfortunately (for the project, good for me) I’ve been very busy over the summer with paying clients but I’m hoping I can get things finished off this week to allow upload and moderation, then the fun can begin!

I also can’t talk about conferences without mentioning another speaking date I have coming up in November. While the AGI is a national group aimed at representing the interests of the whole UK’s geographic information (GI) industry, they also have smaller groups aimed at bringing together the GI community in different areas. The AGI Northern Group achieves these aims in the North of England with a monthly meeting and this year their first full-day seminar – the AGI Northern Group Where2Now Conference. It’s being held on the 10th November in Harrogate and I’ll be speaking along with a great list of people. Ticket information isn’t yet available but put the date in your diary, check out the linkedIn events page and head over to Tim’s blog for more information on the speakers.

If you’re going to the conference next week and we haven’t met before then please do say “Hi!” I’m really looking forward to it, not just for the great content on offer but also for the opportunity to meet up with some old friends that I haven’t seen in some time, and also to meet some new faces. I’ll close this blog post out though by quoting Tim Waters and his write-up of the SOTM conference, it’ll be interesting to see if the AGI Geocommunity conference can generate just as much emotion:

Yes, I got a bit emotional at the third OpenStreetMap conference, held in the CCC, Amsterdam last weekend – mainly because this globe we are on is the only one we know – we really are mapping our universe, doing it our way. Creating the world we want to live in.
Tim Waters

UPDATE 2011/11/16: It’s now possible to buy a WhereDial “Weasley Clock” just like this one!

Last weekend I went to the Howduino hack day which by good fortune was happening on my doorstep, in Liverpool. The day was organised by two friends of mine – Adrian McEwen and Thom Shannon – who have been doing hardware hacking for quite some time now and wanted to open things up for more people to get involved.

Howduino Logo

The day was partly named after Arduino (with a bit of Scouse humour mixed in – “how do we know?!”). From their website:

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software.

Basically you get a circuit board that has a USB slot, a power slot and a set of digital and analogue inputs and outputs. You can load software onto the circuit board via the USB slot, the software can then run on the board when it is disconnected from the computer and can operate other hardware through the inputs and outputs. Adrian used one of these devices to make the famous Bubblino twitter monitoring bubble machine and the Mazzini power monitoring project. Thom has used it to make, amongst other things, a light tracking mini.

Though Howduino got its name from the Arduino boards, the day was actually more of a general hardware hacking event. Sophie Green spent most of the day making artworks using “brush bots” which were incredibly simple devices made from motors and batteries mounted on toothbrushes. Some people built a “drawbot” from scratch on the day and a few people tried making racing radio controlled cars with movements controlled by twitter hashtags.

My project was suggested by Grant Bell, he thought that I should use to create a “Weasley Clock”. This clock is described in the Harry Potter books by J.K. Rowling, it is used by the Weasley family to see where each member of the family is. Instead of telling the time, each hand shows a photo of one of the family members, the clock face has a number of locations written around the edge, such as “Home”, “Travelling”, “School”, “Holidays” and even “Mortal Peril”!

Weasley Clock

Now one way in which I could’ve handled this would be to create a web page that showed my location on a picture of one of these clocks. That would be fairly easy to do but much less interesting than the hardware hacking version. I started off by getting hold of an old clock. My Dad has been tinkering with and fixing clocks for years, and often gets given old clocks and told “This stopped working years ago, thought you might like it” so fortunately he has a few lying around and gave me this one:


I spent a morning taking it to pieces carefully and working out how it worked, until I pulled the back off it and the chime spring caused an explosion of gears:

Howduino preparation

I then took all the bits to Howduino together with a stepper motor that I’d taken out of a floppy drive. After a short while working with Aaron from Oomlout we managed to get the stepper motor going but then I had the problem of connecting the motor to the clock. After many hours of trying to glue and solder the small stepper motor on I finally decided to ask around to see if anyone else had stepper motors. Fortunately someone did, a much bigger motor that could fit through the black of the clock mechanism and unbelievably had a gear on that meshed perfectly with the gears in the clock. With the application of some super glue and a few pieces of metal “salvaged” from an old printer I got the motor attached and turning the hand reliably:

Once that was done I had to write some software. The software for moving the clock is fairly simple. As the motor is a “stepping” motor it can be controlled very reliably. One step of the motor moves it by a well defined amount, with the gearing from the clock 150 steps of the motor turns the minute hand around in a complete rotation, meaning 12 × 150 = 1800 steps will turn the hour hand around completely. I knocked up some Arduino code that reads the current location of the hands from the EEPROM memory on the Arduino. To reset it I manually move the hands to “midnight” and zero the EEPROM memory. I can then tell the Arduino to position each of the hands by an hour. As the hands are still geared together I can only put the hour hand between one hour and another, while the minute hand can be precisely positioned. When the clock has moved to the position you’ve requested, it saves the new location of the hands to the EEPROM memory again so that it’s safe to be powered off.

To get my location I’ve knocked up a MapMe_At class which can request the location for a user. It makes a HTTP request to, using the Arduino Ethernet Shield, pulls down the location and uses a very lightweight JSON parser to pull out the label for the favourite location that I’m currently at. From my core code I then request the location of two users from every minute, convert that location to a position on the clock and then move the hands. When it works it looks really good, I’m only running the clock forwards at the moment because some of the gearing for the chime is still there and makes funny noises if I run the clock backwards, this means that it can take nearly a minute for the hands to move but considering it’s unlikely for location changes to happen that often this should be fine. I do seem to have a problem whereby the clock stops working after running for a while so I’ll have to do some debugging, but as you can see from the photos and the video it is looking pretty good at least!

Weasley Clock

Weasley Clock

(Unfortunately hardware hacking can have its casualties, as you can see the glass on the face of the clock was one)

I’ll be taking the clock along with me on the next Tech Bus Tour from London to Liverpool. I’ll be updating the face to show our progress between the locations as this should be more interesting than showing that I’m “Travelling” constantly. I’ll also open source the Arduino source code when I get around to tidying it up.

UPDATE 2011/11/16: It’s now possible to buy a WhereDial “Weasley Clock” just like this one!

UPDATE 2009/01/04: The code is now available on github, I haven’t had time to fully clean it up and add comments throughout but hopefully it’ll be useful anyway. Download the code here.

If you’ve been following my Twitters you’ll be well aware that I’ve just spent the past week in San Francisco. I came here to attend, and speak at, the launch event for CloudMade’s new APIs for location based services. CloudMade is a company that was launched around 18 months ago by Steve Coast, the founder of the OpenStreetMap project, and Nick Black, a core member of the OSM project. The aim of their company is to bring the power of crowd sourced data, specifically OSM data, to more developers and to commercial companies around the world. The first step of this was of course to develop some products to make this possible and to make them available to the world, hence this event.

The event was split into four main sections. Steve started by giving an overview of the OSM project, its history and some glimpses of what’s likely to happen in the future. Nick then came on stage to explain their ideas behind forming CloudMade and what they’re doing to get OSM data into the hands of more people. After this I and four other developers who have been working with CloudMade’s APIs got on stage to give 5 minute presentations about our experiences developing with the new APIs.

Andrew Turner, CTO of GeoCommons, explained how they have integrated CloudMade’s tiles into their Maker application and talked about how the new Style Editor enables great looking mashups. Jaak Laineste of Nutiteq told us how they’ve been integrating CloudMade’s tile, geocoding and routing services into their Mobile map libraries. I talked about my experiences working with the new APIs, though I won’t go into too much detail here as I wouldn’t want to spoil the surprise for Thursday. Andre, of Advanced Flash Components, then showed us a live demo of CloudMade’s APIs being used in a flash application and showed the speedy responses that the API gave.

Cragg Nilson then talked more about the specific products that CloudMade are making available and how people can get access to them. Finally a Q&A session allowed some light interrogation of the CloudMade team before we moved into another room for demo sessions. Jaak, Andre and I all had a plasma screen each that we used to demo what we’d discussed in our talks. The CloudMade team also demoed various other applications that were using their services, centred around a large range of mobile devices that are able to access the APIs using various applications.

I’ve been really impressed by what CloudMade are offering considering they are still a young company. While a large reason for the quality of their offerings is down to the great team they’ve built up, they do also have an advantage in that the data they’re using, and the license it’s built upon, allow them to offer so much more to the developers using their products. The OSM dataset is incredibly rich and can cover a wide range of features that often don’t get much coverage from standard data providers. Also because the data is free CloudMade can make all of it available in their APIs without having to worry about extra charges such as you might get if you wanted to return vectors from existing data providers.

Now the good news, if you’re reading this thinking “I wish I could’ve gone to San Francisco and seen these great talks”, you need not fret. The whole event is being repeated in London on Thursday 12th. It’s currently oversubscribed but if you are interested in going I believe they’ve managed to arrange extra room so there shouldn’t be a problem with more people going. This page should give more details about the CloudMade launch event in London.

Oh yes, and as a hint to what I’ll be talking about on Thursday, take a look at the new logo for one of my existing mapping sites: logo

I spotted this article about postcodes on the BBC a few days ago. It points out how UK postcodes in their current form have been around for almost 50 years. Postcodes are of course hugely important. Though there have been stories over the years of Royal Mail managing to deliver poorly addressed, or even cryptically addressed items, the fastest and most reliable of getting a letter delivered is to make sure you address it with a postcode. Postcodes are also being used increasingly by personal navigation devices and online mapping services as a really simple and short way of identifying locations.

Considering how important and useful postcodes are, you would think that the post office would want to make it as easy as possible to get hold of information relating to postcodes. On the contrary, while it’s not particularly hard, it is prohibitively expensive. This, of course, is where the Free the Postcode project comes in. As such I’d like everyone reading this blog to make sure in this coming 50th year of postcodes that they submit as many postcodes to Free the Postcode as they can. Hopefully someone will make an Android, J2ME or Symbian app to make this easy, but in the meantime if you have an iPhone then there’s a new version of iFreeThePostcode available to you now.

I’ll talk about the new version in a moment but first I thought I’d mention how successful the app has been so far. My main source for statistics has been iTunes Connect, this is part of iTunes you generally don’t see. This is what I used to upload the app originally and setup my contracts. Apple also provide some basic sales data which can be downloaded in tab separated files. When I added the app I was able to choose what stores to make it available in but I decided not to limit it, so that visitors to the UK would still be able to help if they wanted to. Using the files I’ve found these are the top 5 countries that have downloaded the app:

GB 1683
US 535
CA 77
FR 69
IT 66
Others 684
Total 3114

With so many people downloading the app you might think we’d had huge numbers of submissions to Maybe 2 per person, home and work? Or at least 1 per UK person to download? Well, while that hasn’t been the case, I’ve found that over the past month and a half since the app was released, nearly 50% of postcodes submitted to have come from my app. A few days ago I received the following stats from Dom, the administrator of

In November 307 out of 1723 submissions were from iFreeThePostcode.
In December 587 out of 1199 submissions were from iFreeThePostcode.

So in December that was 49% of the submissions, and using a little maths I’m guessing at about 59% for the 9 days in November that the app was available. I’m really happy with that, but hopefully with the bugs ironed out, we’ll be able to get that even higher in the coming months. And so onto the new release…

Two days ago the new version of iFreeThePostcode went live on the app store. I’ve noticed a few negative reviews on the App Store saying things like “I tried to click the button to submit and it didn’t work, 1 star!” It seems that my existing way of telling you that the accuracy of your location wasn’t high enough was a little too subtle. Originally I set the button status to disabled, all this seems to do though is change the text colour from blue to black, not the most obvious change. I also colour the accuracy label red or green depending on whether it’s accurate enough.

iFreeThePostcode v1.0 Screenshot

The new version replaces the overly subtle “disabled” button with a label when the accuracy is not enough, this label also shows when you haven’t submitted a postcode or email address. I’m hoping this label will be clear enough and that people will now try waiting for a more accurate location. It’s a good thing to remember that not everyone installing your app will be a technophile, but then even amongst my techy friends there were people who couldn’t tell why they weren’t able to submit. I’ve also made sure that the app remembers the postcode that you’ve put in. The original version didn’t do this because I wanted to make sure that people didn’t accidentally submit the same postcode in different locations, but I’ve realised that this is unlikely to happen, whereas it’s quite possible that someone might be copying the postcode from an email or a contact, and might want to flick between iFreeThePostcode and another app without the postcode being removed.

If you’ve got an iPhone and have installed the app, please leave some positive feedback on the iTunes page to counteract the negative feedback. If you do have criticisms then contact me directly or leave comments on the blog post and I’ll try to put fixes in the next version. If you own an iPhone and haven’t installed the app, why not?! Head over to the iFreeThePostcode page for more information and for the iTunes link.

Oh yes, final thing to mention, this version is of course open source again, see the above link to download if you’re interested in finding out how it works. Patches welcome!

BarCamp Liverpool Logo

Wow, BarCamp was such a long time ago. Though I had an amazing weekend and felt really inspired by the end of it, real work brought me back down to earth pretty quickly 🙁

So far I’ve only been to one BarCamp, in Manchester, that was really good but only lasted for one day. I’ve also been to a WhereCamp which is basically the same thing specialising in location based services, this one did involve an overnight stay and was also fun (this one actually took place in the Googleplex!). Having had so much fun away from home I was really looking forward to having a BarCamp in my home town.

Something that I’ve been planning for a while to do at the next Liverpool Mapping Party, when I get around to organising it, was to prepare a big printout of the OSM coverage of Liverpool, get some stickers printed up with POI icons on them, and invite everybody to place stickers where there was missing POIs on the map. As I hadn’t got around to organising a mapping party I decided to do this at BarCamp and try to get everyone interested in editing the map. Cue me spending 3 hours the week before trying to finish all the surveying of South Liverpool and then spending hours on the Friday before BarCamp trying to input this data and prepare a PDF file of the map, suitable to be printed at A0 size. I managed to email my PDF over to the printers at 2:30 on Friday afternoon, fortunately they managed to get it printed within the hour so that I could pick it up on my way to the iPhone event. Unfortunately though the print-out came out looking great, and the vector-based PDF file had given a great result, for some reason all the road names were missing! This is the second A0 printout I’ve done that has had problems so I’m definitely going to have to spend more time on it if I try again.

South Liverpool is mapped on OSM?!

This is a photo of the map at the beginning of the weekend. Unfortunately it didn’t look much different at the end, only a few people bothered putting stickers on it. This was a little surprising to me but I guess that actually most of the people at BarCamp were from outside of Liverpool, and most of the ones from within Liverpool were from the parts that had been mapped. There was also an issue that the map was at such a small scale, and the stickers so big, that each one covered an area of about 1km2. I think the idea could still work but definitely needs to to be done with a larger scale map, more like the type of area you’d try to cover at a mapping party.

The talks at BarCamp were quite varied. Unfortunately as it has been so long now I can’t remember too many of the ones I went to, and I haven’t been able to find a full set of photos of the sessions board. Adrian did a good writeup here that you should read. I do remember a few of the sessions I went to though including one from Gill Hunt of Liverpool Ventures who talked about VCs and how to look for funding. Last thing on Saturday there was also the “Bitchin’ Pitches” session. I used this one to talk about my iPhone app iFreeThePostcode, it was good to get up alongside all the other pitches and talk about my app, but as I wasn’t really looking for money or anything like that there wasn’t actually all that much point and I didn’t end up winning a prize.

In the evening we all went to the bar downstairs at which Microsoft was sponsoring drinks. Beer tokens were handed out by the organisers which we all dutifully exchanged for beer at the bar. The “Bitchin’ Pitches” session also continued into the party with the best pitches being repeated in front of everyone. Melinda Stockington pitched her idea of a site that allowed you to log how often you read books and Adrian pitched his Arduino based Mazzini project for which he won first prize!

Due to the effectiveness of the MS sponsored drinks we were a bit late arriving on the Sunday but when I got there I decided to go for the “Let’s talk about sex” session as I couldn’t find anything else that interested me. I wasn’t really sure what to expect from a load of Geeks talking about sex, it wasn’t quite as scary as you might expect though and most of it was a discussion of relationships and the Internet, including things such as the volatility of the “relationship status” on Facebook. Much amusement when someone suggested the use of HTTP error codes in sexual situations, the following being the ones I found most amusing:

  • 411 Length Required
  • 413 Request Entity Too Large
  • 405 Method Not Allowed
  • 416 Requested Range Not Satisfiable

I don’t know if we covered normal status codes on the day but I just noticed the following could be used too:

  • 100 Continue
  • 201 Created (pregnancy ensues!)

After this I went to a talk about “CodeWiki” which unfortunately I wasn’t really paying attention to at the time. This was followed by John O’Shea’s discussion about his Meat License Proposal. Again I wasn’t really paying attention at first, sitting at the back playing on my laptop. After a while though his talk made me pay attention, basically he’s proposing that to eat meat a person might have to obtain a “Meat License”. To get a license the person would have to have killed an animal with their own hands. It sounds fairly grotesque, but I found it a really interesting proposal and raises some good questions about how much we know of what goes into making the food we eat. Afterwards I talked to John about some work that he’s done as co-director of an artist’s collective that could make some good use of maps, hopefully I’ll be in touch with him again soon (just as soon as I get around to replying to his email!)

Later on in the day I gave a talk about the use of location tracking services on the iPhone. Really it was just to give me an opportunity to talk about and get some opinions of what people expected from this type of service. It was also good to chat to Paul Stringer about his experiences from creating Coffee Buzz.

The final talk that I went to was Adrian’s Don’t Just Change the World… Improve It!. This was a good inspirational talk, it reminded us that the North-West was the birthplace of the industrial revolution and probably has a few environmental debts to repay, so if we can get involved with this side of things it would be a great way to repay those debts. Maybe I just liked his talk because his last slide was one of my photos!

This artwork was actually just outside the door to the venue for BarCamp and it really summed up Adrian’s talk well, this quote is definitely something to live by:


First law of the cosmos

I am now a “published” iPhone developer. My first app – iFreeThePostcode – went live on the app store a week ago, you can find more information about it on this page.

Before October I had never written Objective-C. Also I haven’t written a huge amount of C over the years, so it was quite interesting to try this out. Every time I’d looked at Objective-C so far I’d always thought it looked a bit odd with the crazy square brackets and the strange method names. In fact here’s a sample from iFreeThePostcode, this is a basic function that receives a new location, stores it for later use and passes it on to another object too:

At Liverpool GeekUp in September Dave Verwer gave a talk about iPhone development. It was quite a basic talk but afterwards I was talking to Dave and he suggested I tried reading “Cocoa Programming for Mac OS X” by Aaron Hillegass. I also got the same recommendation from Colm McMullan, creator of Yofe, so I decided it must be worth reading. I read the whole book while on holiday and the following week set about writing my first app. If you’re planning to start writing iPhone apps I’d definitely recommend this book, if you feel like using the Amazon link on the right then I’ll even make money when you buy it!

My first app was actually not iFreeThePostcode but was in fact a routing app. I’ve taken the Gosmore routing library from Open Street Map, the same library that’s used for, and have ported it to Objective-C. It actually works really well on the iPhone and can give speedy routes, though so far I’ve had to limit it to small datasets. Hopefully that’s a limitation I’ll be able to work around. It was when I was ready to add the GPS support to this app that I decided it would probably be easier to try with a simpler app first, and from there iFreeThePostcode was born.

iFreeThePostcode is a ridiculously simple app. The aim of it is to allow you to submit postcodes to the Free the Postcode project. This is a project to create a public domain postcode database in the UK, a much cheaper option than the existing database which costs a lot when bought from the Royal Mail. When you start up the app it shows you a few text boxes and your current latitude and longitude (or “Loading…” initially). Your horizontal accuracy is also shown and will start off in red. When your accuracy goes below 100m it will turn green and you will be able to submit your postcode. You have to enter the postcode as two separate parts, i.e. “EC4A2DY” would be entered as “EC4A” and “2DY”. You also need to enter a valid email address, this is to stop spammers sending useless data and to allow some tracking of who has submitted what postcodes. If someone is found to be submitting copyrighted data, their submissions could therefore be removed. Once you click submit you should get a success or failure message. Failures can be caused by not entering a valid email address or postcode, or by problems communicating with the server. If your submission succeeds you will receive an email containing a special link. Click on the link and your submission should show up in the current public domain list of UK postcodes the next day!

I really hope that by making submissions to Free the Postcode really easy that a lot more postcodes will be submitted. Obviously this is only useful to iPhone users but by most accounts there’s a lot of us out there, also this might inspire someone else to write a similar app for Android, Symbian or Windows Mobile phones which would take the idea to even more people.

Though there’s not a lot of code in this app I’ve decided to make it open source. Hopefully it will help someone who’s looking to get started with iPhone development. A few of the more interesting parts would be the code for handling the current location and the code for submitting the postcode to the website. To download the source code head over to the iFreeThePostcode page. The code that I’ll make available initially is basically the same as the code that is live except that I’ve gone through it to add some more comments. There are a few bugs that I’m aware of though and I’ll work on them soon and release a new version to the app store as soon as they’re done. For more information keep an eye on that page.

I can finally announce, after first mentioning it two months ago, that my new web app is live. is a really simple app that lets you get access to maps easily, no matter what browser you’re using. To view a map of a location just put the name of the location after the slash in the URI. So to see a map of New York, for instance, just go to york. You can see a route between two places by just listing the two places with a slash between them. To get a route between two UK postcodes you could go to 2dy/ec1n 2ns.

It’s such a small and simple app that there’s not really much else left to say in this blog post. Please head over to the site, take a look at the examples and have a play. I’ll be adding more features in the coming days and weeks so it’s worth keeping an eye on it. If you have any suggestions for new features or have any problems, I’m experimenting with Get Satisfaction for this project so head over there and let me know your thoughts.

I realise it hasn’t only been 2 months since I sent that twitter but also since my last blog post. I’ve got one nearly completed and a few more in mind so hopefully there’ll be more soon. I’ve also been posting more recently to so head over there if you haven’t seen it, hopefully there’ll be a few more posts on there soon as well.

UPDATE: Some sites don’t handle single line queries too well and can be improved by sending the country code as a separate parameter. You can now do this by putting a colon followed by the country code after your query, for example, – more examples on the site:

A few days ago I spoke at GeekUp Liverpool about a site that I’ve been playing around with for just over a year. This is the second time I’d spoken publicly about it, the last being at WhereCamp, so I thought I really should put something on my blog too. is a site that I’ve been working on to allow me to log my location in a number of different ways. I originally set it up after the BBC/Yahoo Hack Day in 2007 as somewhere to put the code that I’d written for tracking my location using DNS. Since then I unfortunately haven’t really had much time to spend on it but have managed to develop some parts of it so that it has, for instance: FireEagle and Twitter (direct messages) integration, mapping location through DNS, email, web and mobile app, and the beginnings of a social network aspect.

I recently set-up a blog for it too, the first post highlights a few of the reasons that I think location tracking can be useful on the web. I’ll probably go into more details on that in future posts too. The second post is more instructional, about signing up and creating your first “favourite” on the site, again I’ll likely write a few more posts along those lines. I’m also hoping to go into some detail on the development of the site, including some issues I come across – the first of which is likely to be looking at methods of removing errors that my GPS sends through to the site.

Though the site has been in development for over a year, I really been able to put much time into developing it, tending to add a feature that I want from time to time. Also the site is in definite need of some sprucing up, hopefully I’ll get to that, or get someone else onto it soon. That said it’s quite functional and has a number of interesting ways that you can use to log your location, so get on there and set yourself up with an account or read more over on the blog.

Trace of a 5k run on the River MerseyTrace of a 5k run on the River Mersey
(straight lines are my trip from and to home which I didn’t trace).

Muki Haklay recently put together a blog post about a report that he has been working on over the past year on the evaluation of Open Street Map (OSM) data. I thought I’d link to it here partly to highlight the interesting work he’s done here and also to make a few comments. If you’re at all interested in the OSM project then be sure to head over there and read it.

One of the aspects that I thought he may have missed relates to the way OSM relates the history of OSM entities. A comment I made on his blog follows:

As far as I can tell though the research doesn’t take into account the history of elements in OSM? When you’re looking at the number of users that have worked on an area, you may actually be discounting users who have worked on an area in the past but whose username was then replaced by later edits? I think it’s very important to take this into account as the very peer-reviewing that you are demanding can actually result in the appearance of *less* usernames.

His reply makes it clear that he has thought of this and that he’s happy that by inspecting the data at the level of nodes this is less likely to be an issue. It’s true that in the majority of cases a fix would involve simply moving a node or two along a way. Even though both of the main editors now give you the ability to move a whole way (and all the nodes) at once, which would result in the replacing of the username on the way and all nodes, I’ll admit that this is unlikely to happen very often. That said though, I’m still a little nervous about completely ignoring the history. Any comparison that concentrated on nodes, e.g. only POIs, rather than ways and nodes would have to take this into account much more but clearly Muki’s aware of this and is likely to take it into account in the future.

The report (and indeed the blog post) features the above image showing the difference in coverage between OS Meridian and OSM across England. Blue areas show where OSM coverage is good and red shows bad coverage (compared with OS Meridian). I was initially disheartened by the big red blob over Liverpool and most of the North of England. When I looked at the full size version and squinted a bit I was able to see that South Liverpool shows up as a very small blue smudge amongst the red. The following image is a closeup featuring Liverpool and Manchester. From this it’s much easier to see the South Liverpool and Chester are actually pretty well mapped as well as the South West quadrant of Manchester and a few other places, but the majority of the North needs work. Think we need to get some mapping parties planned!

(It’s also worth noting that the data used for this is at least a few months old by now too, I know the Wirral is looking much better these days and some work is being done on Manchester and Leeds)

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