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CycleStreets blog

News from CycleStreets

Archive for December, 2009

I can’t find my Postcode

Wednesday, December 30th, 2009

It is very possible that you will not be able to find your own postcode using the CycleStreets search. This is due to the data source of postcodes that we are using, and you can contribute too.

CycleStreets could use the Royal Mail’s Postcode Address File (PAF), however that is very expensive at over £5,000 (and some postcodes can be inaccurate). Instead we are using data from two sister projects of OpenStreetMap (where the data for the routing engine comes from). These are FreeThePostcode and NPE Maps. At some point in the future postcode data in OpenStreetMap will be included too.

(If you have a spare £5k hanging around, that would enable us to obtain the PAF, let us know!)

Adding postcodes if you have a mobile phone with a GPS in:

  • If you have an iPhone 3G there is a really easy way to add more postcodes to the data set, thus allowing you to enter that postcode in the future. First up install the iPhone App iFreeThePostCode and then go to the place that you want to add with your iPhone and start the app. You will need to allow location services while the phone searches gets your current location. Enter the postcode and when the accuracy is below 75 metres you will be able to submit your postcode and within a fortnight it will be available for searching. You will normally need to be outside to get the good GPS accuracy.
  • If you have an Android phone you can use either andnav or freethepostcode available from the Android Market.
  • If you are using a J2ME-compatible phone with an internal or bluetooth GPS, then you can install a program called TrackMyJourney. These apps have the ability to submit postcodes too, however require more technical ability to manage.

Shaun

IE8 users: Add our ‘Accelerator’ for the photomap search

Monday, December 28th, 2009

Internet Explorer 8 has a useful new feature called ‘Accelerators‘. We’ve created an Accelerator for the CycleStreets photomap search. It basically gives you a one-click search for photos for a given bit of text.

To get our Accelerator for IE8, go to our Search page, click on the blue install button.
Then confirm, ideally clicking on the tickbox to make this appear more clearly:

Click to confirm

So now it’s installed, how do I use it?

Just highlight some text on a webpage, e.g. ‘potholes’, and a little blue button will appear. Then just click on the CycleStreets entry:

Highlight some text ...

and you’ll then get photos for what you highlighted:

Enjoy!

Posted by Martin (a Google Chrome fan!)

Last 2009 journeys

Friday, December 25th, 2009

For a bit of fun I realised I could plot the start points of planned journeys on the photomap. I’ve done this for the last 2009:

The blue markers indicate the approximate location of recently planned journeys.

Reducing Wiggliness

Tuesday, December 22nd, 2009

In its desire to avoid busy roads, the Journey Planner sometimes finds complicated cycling routes that have many turns. We have come to talk of this problem as wiggliness.

We’ve started work on changing the journey planner so that it finds a better balance between the quietness of a route and the number of turns. The first step has been to define a way of measuring the wiggliness.

We have chosen a simple percentage score, dividing the number of turns in a route by the total number of junctions. This means a route can score between 0%, for a route that goes straight on at every junction, to 100% where a turn is made at every opportunity.

This score is now included on the summary of the journey listing pages, and we’ll use these figures when we receive route feedback to help us monitor the quality of routes.

Ways to get involved with CycleStreets

Friday, December 11th, 2009

We’ve added a new page: Ways to get involved with CycleStreets.

Do get in touch if you can offer any help!

PS We’ve just reached the 20,000th photo in the Photomap!

Faster Routing using A* Algorithm

Thursday, December 10th, 2009

Over the past month we’ve changed the algorithm that searches the map to find routes. It is now much more like the A*search algorithm. The results it produces are identical to those produced previously, but it happens faster.

A* is fast because it uses a clever way of minimizing the amount of map it needs to check to find a route. From the start point the distance as the crow flies to the finish can easily be estimated from the map using geometry (if you had a paper map you could measure it with a ruler and refer to the scale). To search for a route, follow these steps:

  1. Examine each of the neighbouring junctions. They may be nearer to or further from the finish.
  2. For each junction record the total of the crow-fly distance from there to the finish and distance travelled from the start point.
  3. Keep a list of the junctions ordered by the total, lowest first.
  4. Repeat these steps for the first junction on the list until either the finish is reached or the list is empty.

This algorithm is actually simpler than previously and has enabled us to refactor and simplify the code. The only hard bit is keeping an efficient ordered list of junctions. Fortunately the language we are using to implement the algorithm (PHP5.3) has recently expanded its library to include SPLPriorityQueue which we were able to use directly.

The effect of these changes has been to speed up this part of the route planning process. This part of the algorithm used to take several tens of seconds to find a 10 mile route across London, but that can now be done in less than 2 seconds. Our attention is now turning to other aspects of the whole route generation process where further time savings can be made.

CycleStreets ‘Highly Commended’ at the ACT Travelwise Awards 2009

Wednesday, December 2nd, 2009

We’re pleased to announce that CycleStreets was awardedHighly Commended‘ in the ‘Travel Plan Innovation of the Year‘ category at this year’s ACT Travelwise Awards.

Martin, right, receives our certificate

Martin, right, receives our certificate

Sadly we didn’t make the top slot, but congratulations to Transport for London – Smarter Travel Unit, who won the overall category.

Read the full list of award winners on the ACT Travelwise website.

Thanks also to Roger at the CTC who arranged payment of our fee – we’re run on a shoestring so this was helpful. Donations remain welcome of course :)

On a personal note, it was great to be back in Newcastle again. Here are a few photos I took:

We welcome your feedback, especially to report bugs or give us route feedback.

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