source: trunk/npemap.org.uk/static/FAQ.html @ 288

Last change on this file since 288 was 288, checked in by Dominic Hargreaves, 14 years ago

Make a start at some consistent styling.

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2<!--#set var="link" value="/FAQ.html" -->
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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 will 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>Where's the data, then?</h3>
32
33<p>We are still in the early stages of collecting data. We want to make
34sure that the data is in an appropriate format, that we have some quality
35control, and that we release the data in an appropriate format, before
36doing so.
37</p>
38
39<p>
40If you desperately want the data sooner, <a href="reportBug.html">get
41in touch</a>.
42</p>
43
44<h3>What maps are you using?</h3>
45
46<p>We have scans of out of copyright OS maps of England and Wales.
47You can <a href="scotlandAndNI.html">register interest in future
48projects involving Scotland and Northern Ireland</a>.</p>
49
50<h3>So can I do what I like with your scans/tiles?</h3>
51
52<p>
53No. The scans and tiles have been placed under a
54<a href="tileLicence.html">licence</a>; they are not in the public
55domain.
56</p>
57
58<h3>Okay; I can use the tiles for some things; can I download the complete set?</h3>
59
60<p>
61Not yet. We need to make sure we've uncovered all the obvious flaws with
62the current tiles (eg human error in cropping and numbering the tiles)
63and have worked out an efficient distribution format.
64<a href="reportBug.html">Let us know</a> if you want to
65use the tiles; please don't try and crawl our tileserver to obtain the entire
66set.
67</p>
68
69<h3>Isn't orthowotsiting an old map hard?</h3>
70
71<p>Luckily we're going to work in the OSGB coordinate system that
72matches up with the grid lines on the map; this means we don't have to
73distort the maps too much. We also are not overly fussy about the
74accuracy, so this step can be done quickly.</p>
75
76<h3>Why don't you use maps created from <a
77href="http://www.openstreetmap.org">OpenStreetMap</a> data?</h3>
78
79<p>Because they are licensed under Creative Commons Share-alike
80licences, so we wouldn't be able to make our data public domain.</p>
81
82<p>There are people who believe that locating a point on a map creates a
83derived work, and hence requires a licence. We don't want to be the first
84to prove them wrong in a court, as that will be pricy.</p>
85
86<p>Also, the OpenStreetMap maps are not yet complete enough to achieve our
87goal of country-wide coverage.</p>
88
89<h3>Will this data be imported back into Free the Postcode?</h3>
90
91<p>It might be, that will depend on someone working out how to store
92partial postcode data in Free the Postcode. We are importing Free the
93Postcode data into our database.</p>
94
95<h3>If you are using scans of old maps, how accurate will the locations
96be?</h3>
97
98<p>Some of the scans are out by a degree or two but they are fairly
99good. We hope to be able to get better than 100 metres accuracy out of it in
100the end. This is more than good enough to locate a region as large as
101the first half of a postcode, and hopefully as much as the 'partial'
102postcodes described in the answer to 'What is it?' above.</p>
103
104<h3>My house isn't on a 1950s map</h3>
105
106<p>Find some local landmarks and guess where your house is. This is
107accurate enough for our purposes.</p>
108
109<h3>I know exactly where I am, and what my postcode is</h3>
110
111<p>If you have a GPS, enter your data into <a
112href="http://www.freethepostcode.org">Free the Postcode</a> and make the
113world a better place.</p>
114
115<h3>So, how do I use it?</h3>
116
117<p>Find your location on our map, click where your postcode is, enter
118the postcode, agreeing to release your data.</p>
119
120<h3>Psst, I have a copy of the codepoint database. Wanna look?</h3>
121
122<p>No thanks, we want free data so we don't have to keep paying the nice
123codepoint people. </p>
124
125<h3>Won't you drive codepoint out of business?</h3>
126
127<p>We don't think so. There are a lot of places where this level of
128accuracy just isn't enough. Those people will still have to pay until
129<a href="http://www.freethepostcode.org">Free the Postcode</a> improves
130its coverage.</p>
131
132<h3>The map doesn't join up.</h3>
133
134<p>Yes, it isn't perfect. The OS didn't publish a single map of the whole
135country, so you have to scan then stick together data from several maps.
136We don't really know how to correct it perfectly. It would be really cool
137if someone could write software to detect the gridlines and automatically
138cut the images up on the lines and make them square.</p> 
139
140<h3>The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.</h3>
141
142<p>Cool. Contact us, that would be great.</p>
143
144<h3>Why didn't you use proj/gdal?</h3>
145
146<p>Because we don't know how to work them. If you feel like improving how this
147works, let us know.</p>
148
149<h3>Why don't you have good mapping data of Scotland and Northern Ireland?</h3>
150
151<p>I don't think they were part of the New Popular Edition at 1 inch to the
152mile. If you have free higher resolution images of either of these places
153(we only have quarter inch to the mile) then we might be interested in them.</p>
154
155<h3>Who did the work?</h3>
156
157<ul>
158<li>Richard Fairhurst acquired and scanned the maps,</li>
159<li>Dominic Hargreaves and David Sheldon straightened and tiled the maps,</li>
160<li>Matthew Westcott, David Sheldon, Dominic Hargreaves and Nick Burch worked on the user interface and backend software.</li>
161</ul>
162
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