source: trunk/npemap.org.uk/static/FAQ.html @ 657

Last change on this file since 657 was 657, checked in by Nick Burch, 11 years ago

Re-order code bit of faq

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1<!--#set var="title" value="FAQ" -->
2<!--#set var="link" value="/FAQ.html" -->
3<!--#set var="shownav" value="yes" -->
4<!--#include virtual="inc/header.shtml" -->
5
6<ul>
7<li><a href="#whatIsIt">What is it?</a></li>
8<li><a href="#licence">What licence does the data have?</a></li>
9<li><a href="#junkMail">Will I get more junk mail if I enter my postcode?</a></li>
10<li><a href="#whatMaps">What maps are you using?</a></li>
11<li><a href="#doAnything">So can I do what I like with your scans/tiles?</a></li>
12<li><a href="#download">Okay; I can use the tiles for some things; can I download the complete set?</a></li>
13<li><a href="#worldFiles">It'd be really great if I could get a world file / .jpw / etc</a></li>
14<li><a href="#orthorectifying">Isn't orthowotsiting an old map hard?</a></li>
15<li><a href="#openstreetmap">Why don't you use maps created from OpenStreetMap data?</a></li>
16<li><a href="#freethepostcode">Will this data be imported back into Free the Postcode?</a></li>
17<li><a href="#accuracy">If you are using scans of old maps, how accurate will the locations be?</a></li>
18<li><a href="#houseMissing">My house isn't on a 1950s map</a></li>
19<li><a href="#gps">I know exactly where I am, and what my postcode is</a></li>
20<li><a href="#islands">I can't seem to find a certain island on your overview map</a></li>
21<li><a href="#howToUse">So, how do I use it?</a></li>
22<li><a href="#code">Is the code behind the site available?</a></li>
23<li><a href="#codepoint">Psst, I have a copy of the codepoint database. Wanna look?</a></li>
24<li><a href="#otherdata">Here's another source of free postcodes</a></li>
25<li><a href="#codepointBusiness">Won't you drive codepoint out of business?</a></li>
26<li><a href="#tileJoins">The map doesn't join up.</a></li>
27<li><a href="#helpOrthorectifying">The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.</a></li>
28<li><a href="#gdal">Why didn't you use proj/gdal?</a></li>
29<li><a href="#scotland">Why did it take you so long to have good mapping data of Scotland?</a></li>
30<li><a href="#northernIreland">Why don't you have mapping data of Northern Ireland?</a></li>
31<li><a href="#who">Who did the work?</a></li>
32</ul>
33
34<hr />
35
36
37<a name="whatIsIt"></a>
38<h3>What is it?</h3>
39
40<p>There are a lot of applications on websites for being able to tell where
41people are from their postcode. For example "Where is my nearest
42B&amp;Q?". Unfortunately this data is expensive to licence (a few
43thousand pounds/year for a website). <a
44href="http://www.freethepostcode.org">Free the postcode</a> are doing a
45good job, but it is hard to contribute to their database as you
46need a GPS, so they have few postcodes.</p>
47
48<p>Our goal is to collect postcode data by getting users to locate
49themselves on a map of the country. They need only give the first part
50of their postcode, and if we can collect locations for all of these
51parts then we can create a database that is good enough for many
52applications. We are also accepting complete postcodes and 'partial'
53postcodes including the number portion of the second half of the postcode,
54in order to improve our accuracy.
55</p>
56
57
58<a name="licence"></a>
59<h3>What licence does the data have?</h3>
60
61<p>The data will be will be in the public domain; consequently, users
62submitting data agree to their submission being in the public domain
63when they enter their postcode.</p>
64
65
66<a name="junkMail"></a>
67<h3>Will I get more junk mail if I enter my postcode?</h3>
68
69<p>
70No, we are just interested in where the postcode is. We don't collect
71your name or house number. Please see our <a href="/privacy.html">privacy policy</a>.</p>
72
73
74<a name="whatMaps"></a>
75<h3>What maps are you using?</h3>
76
77<p>We have scans of out of copyright OS maps of England, Scotland and Wales.
78You can <a href="scotlandAndNI.html">register interest in future projects
79involving Northern Ireland</a>.</p>
80
81
82<a name="doAnything"></a>
83<h3>So can I do what I like with your scans/tiles?</h3>
84
85<p>
86No. The scans and tiles have been placed under a
87<a href="tileLicence.html">licence</a>; they are not in the public
88domain.
89</p>
90
91
92<a name="download"></a>
93<h3>Okay; I can use the tiles for some things; can I download the complete set?</h3>
94
95<p>
96We have all the tiles available in a couple of different naming schemes, but
97not all of them are on machines with suitable internet connections for
98downloading from.</p>
99
100<p>If you <a href="reportBug.html">drop us an email</a> letting us know which
101areas you are interested in (ideally either sheet numbers, or the whole lot),
102and confirm that your use falls within <a href="#licence">the tile
103licence</a>, we can work out the best way to let you get the tiles. It may
104even be possible for us to post you a dvd of the tiles, but we'll normally
105request a donation to <a href="http://www.openstreetmap.org/">OpenStreetMap</a>
106in-leui of the postage.
107</p>
108
109<p>One thing we do ask is that if you want to use the tiles; please don't
110try and crawl our tileserver to obtain the entire set.
111<a href="reportBug.html">Let us know</a> what you're after, and we can
112probably sort something out!
113</p>
114
115
116<a name="worldFiles"></a>
117<h3>It'd be really great if I could get a world file / .jpw / etc
118 for the tiles I'm looking at, so I can feed it to gdal / mapserv / etc</h3>
119
120<p>It's very easy to turn a tile's URL into the location of any of its
121 corners. We have a script that will happily spit out .jpw world files for
122 any of our tiles, which various people make use of.</p> 
123
124<p><a href="reportBug.html">Let us know</a> if you're interested, and we
125 can either send you a bunch of world files, or the magic perl script.</p>
126
127<p>You may also be interested in the WMS server of the tiles run by
128 <a href="http://www.blacksworld.net/">Nick Black</a>. He gives the details
129 of it in <a href="http://www.blacksworld.net/blog/?p=83">this blog post.</a>
130</p>
131
132
133<a name="orthorectifying"></a>
134<h3>Isn't orthowotsiting an old map hard?</h3>
135
136<p>Luckily we're going to work in the OSGB coordinate system that
137matches up with the grid lines on the map; this means we don't have to
138distort the maps too much. We also are not overly fussy about the
139accuracy, so this step can be done quickly.</p>
140
141
142<a name="openstreetmap"></a>
143<h3>Why don't you use maps created from <a
144href="http://www.openstreetmap.org">OpenStreetMap</a> data?</h3>
145
146<p>Because they are licensed under Creative Commons Share-alike
147licences, so we wouldn't be able to make our data public domain.</p>
148
149<p>There are people who believe that locating a point on a map creates a
150derived work, and hence requires a licence. We don't want to be the first
151to prove them wrong in a court, as that will be pricy.</p>
152
153<p>Also, the OpenStreetMap maps are not yet complete enough to achieve our
154goal of country-wide coverage.</p>
155
156
157<a name="freethepostcode"></a>
158<h3>Will this data be imported back into Free the Postcode?</h3>
159
160<p>Probably not directly. We are looking at the best way of presenting
161data from both projects whilst not polluting the Free the Postcode database
162with our lower accuracy data. We are importing Free the Postcode data into
163our database for display, but not re-exporting it currently.</p>
164
165
166<a name="accuracy"></a>
167<h3>If you are using scans of old maps, how accurate will the locations
168be?</h3>
169
170<p>Some of the scans are out by a degree or two but they are fairly
171good. We hope to be able to get better than 100 metres accuracy out of it in
172the end. This is more than good enough to locate a region as large as
173the first half of a postcode, and hopefully as much as the 'partial'
174postcodes described in the answer to 'What is it?' above.</p>
175
176
177<a name="houseMissing"></a>
178<h3>My house isn't on a 1950s map</h3>
179
180<p>Find some local landmarks and guess where your house is. This is
181accurate enough for our purposes.</p>
182
183
184<a name="gps"></a>
185<h3>I know exactly where I am, and what my postcode is</h3>
186
187<p>If you have a GPS, enter your data into <a
188href="http://www.freethepostcode.org">Free the Postcode</a> and make the
189world a better place.</p>
190
191
192<a name="islands"></a>
193<h3>I can't seem to find a certain island on your overview map</h3>
194<p>We've put together a list of <a href="islands.html">hard to find
195 islands</a>, so you might well be able to find it from there.</p>
196
197
198<a name="howToUse"></a>
199<h3>So, how do I use it?</h3>
200
201<p>Find your location on our map, click where your postcode is, enter
202the postcode, agreeing to release your data.</p>
203
204
205<a name="code"></a>
206<h3>Is the code behind the site available?</h3>
207<p>Yes, the code that powers the site is available in a public
208svn repository. You're welcome to check out the code from
209<a href="https://urchin.earth.li/svn/npemap/">https://urchin.earth.li/svn/npemap/</a></p>
210<p>The code is all under an open, MIT like license, see
211<a href="https://urchin.earth.li/svn/npemap/trunk/COPYING">here</a>
212for details.</p>
213
214
215<a name="codepoint"></a>
216<h3>Psst, I have a copy of the codepoint database. Wanna look?</h3>
217
218<p>No thanks, we want free data so we don't have to keep paying the nice
219codepoint people. </p>
220
221<a name="otherdata"></a>
222<h3>Here's another source of free postcodes</h3>
223
224<p>There are many unattributed postcodes sets on the web, but none others
225(apart from freethepostcode.org, which we are already working with) which
226are unambiguously free. In particular there is a <a href="http://www.jibble.org/ukpostcodes/">site</a> which lots of people have pointed at. Unfortunately
227there is no actual data there; the data was removed after the Post Office
228issued a take-down notice to this site. We're only interested in public
229domain database (or possibly databases with other unambiguously "free"
230licensing terms).
231</p>
232
233
234<a name="codepointBusiness"></a>
235<h3>Won't you drive codepoint out of business?</h3>
236
237<p>We don't think so. There are a lot of places where this level of
238accuracy just isn't enough. Those people will still have to pay until
239<a href="http://www.freethepostcode.org">Free the Postcode</a> improves
240its coverage.</p>
241
242
243<a name="tileJoins"></a>
244<h3>The map doesn't join up.</h3>
245
246<p>Yes, it isn't perfect. The OS didn't publish a single map of the whole
247country, so you have to scan then stick together data from several maps.
248We don't really know how to correct it perfectly. It would be really cool
249if someone could write software to detect the gridlines and automatically
250cut the images up on the lines and make them square.</p> 
251
252
253<a name="helpOrthorectifying"></a>
254<h3>The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.</h3>
255
256<p>Cool. Contact us, that would be great.</p>
257
258
259<a name="gdal"></a>
260<h3>Why didn't you use proj/gdal?</h3>
261
262<p>Because we don't know how to work them. If you feel like improving how this
263works, let us know. Update: We do use proj for the <a href="/postcodeine/">postcode display</a>.</p>
264
265
266<a name="scotland"></a>
267<h3>Why did it take you so long to have coverage of Scotland?</h3>
268
269<p>While the Ordnance Survey did create the New Popular Edition maps of
270 Scotland at 1 inch to the mile, these were never published, so we can't
271 buy them to scan in. Scotland was included in the Ordnance Survey
272 7<sup>th</sup> Edition at 1 inch to the mile, but almost all of these
273 maps remain in copyright for another few years, so we can't put them
274 online yet</p>
275<p>The Ordnance Survey did release some updates to the Popular Edition
276 of Scotland in the 1940s, which had the National Grid over-printed on.
277 them. (The War Office also published similar versions). While the grid
278 isn't parallel with the main map, it is possible to work with (just a
279 little bit more work). It has taken us much longer to track these down
280 than it took us to get the England and Wales New Popular Edition maps.
281 This is why we have only recently been able to offer a high degree of
282 coverage for Scotland.</p>
283
284<p>We now think we have completed our coverage of Scotland. Most of the
285 maps used are from the 1940s, but there are small numbers of earlier maps
286 (mostly 1920s), and small numbers of 7<sup>th</sup> edition maps from the
287 1950s. To see the coverage we have, visit the
288 <a href="/tiles/allmaps.html">large overview map.</a></p>
289
290
291<a name="northernIreland"></a>
292<h3>Why don't you have mapping data of Northern Ireland?</h3>
293
294<p>For Northern Ireland, the situation is harder than for Scotland,
295 because the Ordnance Survey of Northern Ireland didn't produce an
296 equivalent to the New Popular Edition, instead it produced a number of
297 updates without altering the name of the edition. So, many of the maps
298 from the Popular Edition of Northern Ireland are still in Copyright, so
299 it's hard to know if a given old map is out of copyright just from the
300 name.</p>
301<p>Compounding this, it is much harder to track down second hand maps
302 of Northern Ireland, compared to the difficulty of getting English,
303 Welsh and Scottish maps of the period. We have also yet to come across
304 any institutional holdings of old Northern Irish maps where the
305 holder will allow scans to be made. All we have been able to get is
306 quarter inch to the mile maps, which don't fit into our tiling scheme,
307 and are too small for finding postcodes on.</p>
308
309<p>If you would like to be notified when we do get out of copyright 1 inch
310 to the mile maps of Northern Ireland, please
311 <a href="scotlandAndNI.html">register your interest</a>.</p>
312
313
314<a name="who"></a>
315<h3>Who did the work?</h3>
316
317<ul>
318<li>Richard Fairhurst acquired and scanned the maps of England and Wales,</li>
319<li>Nick Burch, Andrew Rowbottom and Mike Calder have aquired and scanned
320 the maps of Scotland,</li>
321<li>Dominic Hargreaves, David Sheldon and Nick Burch straightened and tiled
322 the maps,</li>
323<li>Matthew Westcott, <a href="http://www.earth.li/~dave/">David Sheldon</a>,
324 Dominic Hargreaves and Nick Burch worked on the user interface and backend
325 software.</li>
326<li>Nick and Matthew's employer
327 <a href="http://www.torchbox.com">Torchbox</a> has supported the project
328 with some development time and design work.</li>
329</ul>
330
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