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<h3>What is it?</h3>

<p>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&amp;Q?". Unfortunately this data is expensive to licence (a few
thousand pounds/year for a website). <a
href="http://www.freethepostcode.org">Free the postcode</a> are doing a
good job, but it is hard to contribute to their database as you
need a GPS, so they have few postcodes.</p>

<p>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.
</p>

<h3>What licence does the data have?</h3>

<p>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.</p>

<h3>Will I get more junk mail if I enter my postcode?</h3>

<p>
No, we are just interested in where the postcode is. We don't collect
your name or house number. Please see our <a href="/privacy.html">privacy policy</a>.</p>

<h3>What maps are you using?</h3>

<p>We have scans of out of copyright OS maps of England and Wales.
You can <a href="scotlandAndNI.html">register interest in future
projects involving Scotland and Northern Ireland</a>.</p>

<h3>So can I do what I like with your scans/tiles?</h3>

<p>
No. The scans and tiles have been placed under a
<a href="tileLicence.html">licence</a>; they are not in the public
domain.
</p>

<h3>Okay; I can use the tiles for some things; can I download the complete set?</h3>

<p>
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. 
<a href="reportBug.html">Let us know</a> if you want to
use the tiles; please don't try and crawl our tileserver to obtain the entire
set.
</p>

<h3>Isn't orthowotsiting an old map hard?</h3>

<p>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.</p>

<h3>Why don't you use maps created from <a
href="http://www.openstreetmap.org">OpenStreetMap</a> data?</h3>

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

<p>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.</p>

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

<h3>Will this data be imported back into Free the Postcode?</h3>

<p>Probably not directly. We are looking at the best way of presenting
data from both projects whilst not polluting the Free the Postcode database
with our lower accuracy data. We are importing Free the Postcode data into
our database for display, but not re-exporting it currently.</p>

<h3>If you are using scans of old maps, how accurate will the locations
be?</h3>

<p>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.</p>

<h3>My house isn't on a 1950s map</h3>

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


<a name="gps"></a>
<h3>I know exactly where I am, and what my postcode is</h3>

<p>If you have a GPS, enter your data into <a
href="http://www.freethepostcode.org">Free the Postcode</a> and make the
world a better place.</p>


<a name="islands"></a>
<h3>I can't seem to find a certain island on your overview map</h3>
<p>We've put together a list of <a href="islands.html">hard to find
 islands</a>, so you might well be able to find it from there.</p>


<h3>So, how do I use it?</h3>

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


<a name="codepoint"></a>
<h3>Psst, I have a copy of the codepoint database. Wanna look?</h3>

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

<a name="otherdata"></a>
<h3>Here's another source of free postcodes</h3>

<p>There are many unattributed postcodes sets on the web, but none others
(apart from freethepostcode.org, which we are already working with) which
are unambiguously free. In particular there is a <a href="http://www.jibble.org/ukpostcodes/">site</a> which lots of people have pointed at. Unfortunately
there is no actual data there; the data was removed after the Post Office
issued a take-down notice to this site. We're only interested in public
domain database (or possibly databases with other unambiguously "free"
licensing terms).
</p>

<h3>Won't you drive codepoint out of business?</h3>

<p>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
<a href="http://www.freethepostcode.org">Free the Postcode</a> improves
its coverage.</p>

<h3>The map doesn't join up.</h3>

<p>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.</p> 

<h3>The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.</h3>

<p>Cool. Contact us, that would be great.</p>

<h3>Why didn't you use proj/gdal?</h3>

<p>Because we don't know how to work them. If you feel like improving how this
works, let us know. Update: We do use proj for the <a href="/postcodeine/">postcode display</a>.</p>


<a name="scotlandNI"></a>
<h3>Why don't you have good mapping data of Scotland and Northern Ireland?</h3>

<p>While the Ordnance Survey did create the New Popular Edition maps of 
 Scotland at 1 inch to the mile, these were never
 published, so we can't buy them to scan in. All we have been able to get
 is quarter inch to the mile maps, which don't fit into our tiling scheme,
 and are too small for finding postcodes on.</p>
<p>Scotland and Northern Ireland were included in the Ordnance Survey 
 7<sup>th</sup> Edition at 1 inch to the mile, but
 almost all of these maps remain in copyright for another few years, so
 we couldn't put them online.</p>
<p>The Ordnance Survey did release some updates to the Popular Edition
 of Scotland in the 1940s, which had the National Grid over-printed on. 
 them. (The War Office also published similar versions). While the grid 
 isn't parallel with the main map, it is possible to work with (just a 
 little bit more work). We don't have very many of these sheets though,
 so we would love to hear from anyone who does.</p>
<p>If you would like to be notified when we do get out of copyright 1 inch
 to the mile maps of Scotland and Northern Ireland, please 
 <a href="scotlandAndNI.html">register your interest</a>.</p>
<p>For now, our Scottish coverage is limited to:</p>
<ul style="margin-left: 2em">
<li><a href="http://www.npemap.org.uk/tiles/map.html#110,189,2">Gretna</a>,
 <a href="http://www.npemap.org.uk/tiles/map.html#104,193,2">Lockerbie</a>
 and <a href="http://www.npemap.org.uk/tiles/map.html#100,191,2">Dumfries</a>
 (included on the Carlisle New Popular Edition map)</li>
<li><a href="http://www.npemap.org.uk/tiles/map.html#385,640,1">Coldstream</a>
 and <a href="http://www.npemap.org.uk/tiles/map.html#394,664,1">Eyemouth</a>
 (included on the Berwick upon Tweed New Popular Edition map)</li>
<li><a href="http://www.npemap.org.uk/tiles/map.html#86,281,2">Inverness</a>
 (trial area scanned from an Updated Popular Edition map)</li>
</ul>


<h3>Who did the work?</h3>

<ul>
<li>Richard Fairhurst acquired and scanned the maps of England and Wales,</li>
<li>Richard Fairhurst and Nick Burch are aquiring and scanning maps of 
 Scotland,</li>
<li>Dominic Hargreaves, David Sheldon and Nick Burch straightened and tiled 
 the maps,</li>
<li>Matthew Westcott, <a href="http://www.earth.li/~dave/">David Sheldon</a>, 
 Dominic Hargreaves and Nick Burch worked on the user interface and backend 
 software.</li>
<li>Nick, David and Matthew's employer 
 <a href="http://www.torchbox.com">Torchbox</a> has supported the project 
 with some development time and design work.</li>
</ul>

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