source: trunk/npemap.org.uk/static/FAQ.html @ 93

Last change on this file since 93 was 91, checked in by Dominic Hargreaves, 14 years ago

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1<html>
2<head>
3<title>FAQ | New Popular Edition Maps</title>
4</head>
5
6<body>
7
8<h2>Free the postcode lite</h2>
9
10<h3>What is it?</h3>
11
12<p>There are a lot of applications on websites for being able to tell where
13people are from their postcode. For example "Where is my nearest
14B&amp;Q?". Unfortunately this data is expensive to licence (a few
15thousand pounds/year for a website). <a
16href="http://www.freethepostcode.org">Free the postcode</a> are doing a
17good job, but it is hard to contribute to their database as you
18need a GPS, so they have few postcodes.</p>
19
20<p>Our goal is to collect postcode data by getting users to locate
21themselves on a map of the country. They need only give the first part
22of their postcode, and if we can collect locations for all of these
23parts then we can create a database that is good enough for many
24applications. We are also accepting complete postcodes and 'partial'
25postcodes including the number portion of the second half of the postcode,
26in order to improve our accuracy.
27</p>
28
29<h3>What licence will the data have?</h3>
30
31<p>The data will be will be in the public domain; consequently, users
32submitting data agree to their submission being in the public domain
33when they enter their postcode.</p>
34
35<h3>Where's the data, then?</h3>
36
37<p>We are still in the early stages of collecting data. We want to make
38sure that the data is in an appropriate format, that we have some quality
39control, and that we release the data in an appropriate format, before
40doing so.
41</p>
42
43<p>
44If you desperately want the data sooner, <a href="reportBug.html">get
45in touch</a>.
46</p>
47
48<h3>What maps are you using?</h3>
49
50<p>We have scans of out of copyright OS maps of England and Wales.
51You can <a href="scotlandAndNI.html">register interest in future
52projects involving Scotland and Northern Ireland</a>.</p>
53
54<h3>So can I do what I like with your scans/tiles?</h3>
55
56<p>
57No. The scans and tiles have been placed under a
58<a href="tileLicence.html">licence</a>; they are not in the public
59domain.
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>It might be, that will depend on someone working out how to store
85partial postcode data in Free the Postcode. We are importing Free the
86Postcode data into our database.</p>
87
88<h3>If you are using scans of old maps, how accurate will the locations
89be?</h3>
90
91<p>Some of the scans are out by a degree or two but they are fairly
92good. We hope to be able to get better than 100 metres accuracy out of it in
93the end. This is more than good enough to locate a region as large as
94the first half of a postcode, and hopefully as much as the 'partial'
95postcodes described in the answer to 'What is it?' above.</p>
96
97<h3>My house isn't on a 1950s map</h3>
98
99<p>Find some local landmarks and guess where your house is. This is
100accurate enough for our purposes.</p>
101
102<h3>I know exactly where I am, and what my postcode is</h3>
103
104<p>If you have a GPS, enter your data into <a
105href="http://www.freethepostcode.org">Free the Postcode</a> and make the
106world a better place.</p>
107
108<h3>So, how do I use it?</h3>
109
110<p>Find your location on our map, click where your postcode is, enter
111the postcode, agreeing to release your data.</p>
112
113<h3>Psst, I have a copy of the codepoint database. Wanna look?</h3>
114
115<p>No thanks, we want free data so we don't have to keep paying the nice
116codepoint people. </p>
117
118<h3>Won't you drive codepoint out of business?</h3>
119
120<p>We don't think so. There are a lot of places where this level of
121accuracy just isn't enough. Those people will still have to pay until
122<a href="http://www.freethepostcode.org">Free the Postcode</a> improves
123its coverage.</p>
124
125<h3>The map doesn't join up.</h3>
126
127<p>Yes, it isn't perfect. The OS didn't publish a single map of the whole
128country, so you have to scan then stick together data from several maps.
129We don't really know how to correct it perfectly. It would be really cool
130if someone could write software to detect the gridlines and automatically
131cut the images up on the lines and make them square.</p> 
132
133<h3>The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.</h3>
134
135<p>Cool. Contact us, that would be great.</p>
136
137<h3>Why didn't you use proj/gdal?</h3>
138
139<p>Because we don't know how to work them. If you feel like improving how this
140works, let us know.</p>
141
142<h3>Why don't you have good mapping data of Scotland and Northern Ireland?</h3>
143
144<p>I don't think they were part of the New Popular Edition at 1 inch to the
145mile. If you have free higher resolution images of either of these places
146(we only have quarter inch to the mile) then we might be interested in them.</p>
147
148<h3>Who did the work?</h3>
149
150<p>
151<ul>
152<li>Richard Fairhurst acquired and scanned the maps,</li>
153<li>Dominic Hargreaves and David Sheldon straightened and tiled the maps,</li>
154<li>Matthew Westcott, David Sheldon, Dominic Hargreaves and Nick Burch worked on the user interface.</li>
155<ul>
156</body>
157</html>
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