Free the postcode lite

What is it?

There are a lot of applications on websites for being able to tell where people are from their postcode. For example "Where is my nearest B&Q?". Unfortunately this data is expensive to licence (a few thousand pounds/year for a website). Free the postcode are doing a good job, but it is hard to contribute to their database as you need a GPS, so they have few postcodes.

Our goal is to collect postcode data by getting users to locate themselves on a map of the country. They need only give the first part of their postcode, and if we can collect locations for all of these parts then we can create a database that is good enough for many applications. We are also accepting complete postcodes and 'partial' postcodes including the number portion of the second half of the postcode, in order to improve our accuracy.

What licence will the data have?

The data will be will be in the public domain; consequently, users submitting data agree to their submission being in the public domain when they enter their postcode.

Where's the data, then?

We are still in the early stages of collecting data. We want to make sure that the data is in an appropriate format, that we have some quality control, and that we release the data in an appropriate format, before doing so.

If you desperately want the data sooner, get in touch.

What maps are you using?

We have scans of out of copyright OS maps of England and Wales. You can register interest in future projects involving Scotland and Northern Ireland.

So can I do what I like with your scans/tiles?

No. The scans and tiles have been placed under a licence; they are not in the public domain.

Okay; I can use the tiles for some things; can I download the complete set?

Not yet. We need to make sure we've uncovered all the obvious flaws with the current tiles (eg human error in cropping and numbering the tiles) and have worked out an efficient distribution format. Let us know if you want to use the tiles; please don't try and crawl our tileserver to obtain the entire set.

Isn't orthowotsiting an old map hard?

Luckily we're going to work in the OSGB coordinate system that matches up with the grid lines on the map; this means we don't have to distort the maps too much. We also are not overly fussy about the accuracy, so this step can be done quickly.

Why don't you use maps created from OpenStreetMap data?

Because they are licensed under Creative Commons Share-alike licences, so we wouldn't be able to make our data public domain.

There are people who believe that locating a point on a map creates a derived work, and hence requires a licence. We don't want to be the first to prove them wrong in a court, as that will be pricy.

Also, the OpenStreetMap maps are not yet complete enough to achieve our goal of country-wide coverage.

Will this data be imported back into Free the Postcode?

It might be, that will depend on someone working out how to store partial postcode data in Free the Postcode. We are importing Free the Postcode data into our database.

If you are using scans of old maps, how accurate will the locations be?

Some of the scans are out by a degree or two but they are fairly good. We hope to be able to get better than 100 metres accuracy out of it in the end. This is more than good enough to locate a region as large as the first half of a postcode, and hopefully as much as the 'partial' postcodes described in the answer to 'What is it?' above.

My house isn't on a 1950s map

Find some local landmarks and guess where your house is. This is accurate enough for our purposes.

I know exactly where I am, and what my postcode is

If you have a GPS, enter your data into Free the Postcode and make the world a better place.

So, how do I use it?

Find your location on our map, click where your postcode is, enter the postcode, agreeing to release your data.

Psst, I have a copy of the codepoint database. Wanna look?

No thanks, we want free data so we don't have to keep paying the nice codepoint people.

Won't you drive codepoint out of business?

We don't think so. There are a lot of places where this level of accuracy just isn't enough. Those people will still have to pay until Free the Postcode improves its coverage.

The map doesn't join up.

Yes, it isn't perfect. The OS didn't publish a single map of the whole country, so you have to scan then stick together data from several maps. We don't really know how to correct it perfectly. It would be really cool if someone could write software to detect the gridlines and automatically cut the images up on the lines and make them square.

The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.

Cool. Contact us, that would be great.

Why didn't you use proj/gdal?

Because we don't know how to work them. If you feel like improving how this works, let us know.

Why don't you have good mapping data of Scotland and Northern Ireland?

I don't think they were part of the New Popular Edition at 1 inch to the mile. If you have free higher resolution images of either of these places (we only have quarter inch to the mile) then we might be interested in them.

Who did the work?