source: trunk/npemap.org.uk/static/FAQ.html @ 388

Last change on this file since 388 was 388, checked in by David Sheldon, 15 years ago

Make torchbox a link.

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5
6<h3>What is it?</h3>
7
8<p>There are a lot of applications on websites for being able to tell where
9people are from their postcode. For example "Where is my nearest
10B&amp;Q?". Unfortunately this data is expensive to licence (a few
11thousand pounds/year for a website). <a
12href="http://www.freethepostcode.org">Free the postcode</a> are doing a
13good job, but it is hard to contribute to their database as you
14need a GPS, so they have few postcodes.</p>
15
16<p>Our goal is to collect postcode data by getting users to locate
17themselves on a map of the country. They need only give the first part
18of their postcode, and if we can collect locations for all of these
19parts then we can create a database that is good enough for many
20applications. We are also accepting complete postcodes and 'partial'
21postcodes including the number portion of the second half of the postcode,
22in order to improve our accuracy.
23</p>
24
25<h3>What licence does the data have?</h3>
26
27<p>The data will be will be in the public domain; consequently, users
28submitting data agree to their submission being in the public domain
29when they enter their postcode.</p>
30
31<h3>Will I get more junk mail if I enter my postcode?</h3>
32
33<p>
34No, we are just interested in where the postcode is. We don't collect
35your name or house number. Please see our <a href="/privacy.html">privacy policy</a>.</p>
36
37<h3>What maps are you using?</h3>
38
39<p>We have scans of out of copyright OS maps of England and Wales.
40You can <a href="scotlandAndNI.html">register interest in future
41projects involving Scotland and Northern Ireland</a>.</p>
42
43<h3>So can I do what I like with your scans/tiles?</h3>
44
45<p>
46No. The scans and tiles have been placed under a
47<a href="tileLicence.html">licence</a>; they are not in the public
48domain.
49</p>
50
51<h3>Okay; I can use the tiles for some things; can I download the complete set?</h3>
52
53<p>
54Not yet. We need to make sure we've uncovered all the obvious flaws with
55the current tiles (eg human error in cropping and numbering the tiles)
56and have worked out an efficient distribution format.
57<a href="reportBug.html">Let us know</a> if you want to
58use the tiles; please don't try and crawl our tileserver to obtain the entire
59set.
60</p>
61
62<h3>Isn't orthowotsiting an old map hard?</h3>
63
64<p>Luckily we're going to work in the OSGB coordinate system that
65matches up with the grid lines on the map; this means we don't have to
66distort the maps too much. We also are not overly fussy about the
67accuracy, so this step can be done quickly.</p>
68
69<h3>Why don't you use maps created from <a
70href="http://www.openstreetmap.org">OpenStreetMap</a> data?</h3>
71
72<p>Because they are licensed under Creative Commons Share-alike
73licences, so we wouldn't be able to make our data public domain.</p>
74
75<p>There are people who believe that locating a point on a map creates a
76derived work, and hence requires a licence. We don't want to be the first
77to prove them wrong in a court, as that will be pricy.</p>
78
79<p>Also, the OpenStreetMap maps are not yet complete enough to achieve our
80goal of country-wide coverage.</p>
81
82<h3>Will this data be imported back into Free the Postcode?</h3>
83
84<p>Probably not directly. We are looking at the best way of presenting
85data from both projects whilst not polluting the Free the Postcode database
86with our lower accuracy data. We are importing Free the Postcode data into
87our database for display, but not re-exporting it currently.</p>
88
89<h3>If you are using scans of old maps, how accurate will the locations
90be?</h3>
91
92<p>Some of the scans are out by a degree or two but they are fairly
93good. We hope to be able to get better than 100 metres accuracy out of it in
94the end. This is more than good enough to locate a region as large as
95the first half of a postcode, and hopefully as much as the 'partial'
96postcodes described in the answer to 'What is it?' above.</p>
97
98<h3>My house isn't on a 1950s map</h3>
99
100<p>Find some local landmarks and guess where your house is. This is
101accurate enough for our purposes.</p>
102
103<h3>I know exactly where I am, and what my postcode is</h3>
104
105<p>If you have a GPS, enter your data into <a
106href="http://www.freethepostcode.org">Free the Postcode</a> and make the
107world a better place.</p>
108
109<h3>I can't seem to find a certain island on your overview map</h3>
110<p>We've put together a list of <a href="islands.html">hard to find
111 islands</a>, so you might well be able to find it from there.</p>
112
113<h3>So, how do I use it?</h3>
114
115<p>Find your location on our map, click where your postcode is, enter
116the postcode, agreeing to release your data.</p>
117
118<h3>Psst, I have a copy of the codepoint database. Wanna look?</h3>
119
120<p>No thanks, we want free data so we don't have to keep paying the nice
121codepoint people. </p>
122
123<h3>Won't you drive codepoint out of business?</h3>
124
125<p>We don't think so. There are a lot of places where this level of
126accuracy just isn't enough. Those people will still have to pay until
127<a href="http://www.freethepostcode.org">Free the Postcode</a> improves
128its coverage.</p>
129
130<h3>The map doesn't join up.</h3>
131
132<p>Yes, it isn't perfect. The OS didn't publish a single map of the whole
133country, so you have to scan then stick together data from several maps.
134We don't really know how to correct it perfectly. It would be really cool
135if someone could write software to detect the gridlines and automatically
136cut the images up on the lines and make them square.</p> 
137
138<h3>The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.</h3>
139
140<p>Cool. Contact us, that would be great.</p>
141
142<h3>Why didn't you use proj/gdal?</h3>
143
144<p>Because we don't know how to work them. If you feel like improving how this
145works, let us know. Update: We do use proj for the <a href="/postcodeine/">postcode display</a>.</p>
146
147<h3>Why don't you have good mapping data of Scotland and Northern Ireland?</h3>
148
149<p>While the Ordnance Survey did create the New Popular Edition maps of
150 Scotland at 1 inch to the mile, these were never
151 published, so we can't buy them to scan in. All we have been able to get
152 is quarter inch to the mile maps, which don't fit into our tiling scheme,
153 and are too small for finding postcodes on.</p>
154<p>Scotland and Northern Ireland were included in the Ordnance Survey
155 7<sup>th</sup> Edition at 1 inch to the mile, but
156 almost all of these maps remain in copyright for another few years, so
157 we couldn't put them online.</p>
158<p>If you do have free higher resolution images of either of Scotland or
159 Northern Ireland (eg the 1920s Popular Edition, or the War Office Editions),
160 then we would be very interested. Do please contact us if you have such
161 maps.</p>
162<p>If you would like to be notified when we do get out of copyright 1 inch
163 to the mile maps of Scotland and Northern Ireland, please
164 <a href="scotlandAndNI.html">register your interest</a>.</p>
165
166
167
168<h3>Who did the work?</h3>
169
170<ul>
171<li>Richard Fairhurst acquired and scanned the maps,</li>
172<li>Dominic Hargreaves and David Sheldon straightened and tiled the maps,</li>
173<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>
174<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>
175</ul>
176
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