Hi Peter,<div>Thanks for that - I can see another target now - to turn Hartlepool Blue!</div><div><br></div><div>How do 'Trunk' roads fit into yours (and the DfT's) scheme? Someone changed the main road into Hartlepool to be 'Trunk' on the basis that it has green signs, but I have never thought of it as being a significant enough place to have a Trunk road, although it does have green signs. Have you merged trunk and primary?</div>
<div><br></div><div>Regards</div><div><br></div><div>Graham.</div><div><br><br><div class="gmail_quote">On 29 March 2010 17:57, Peter Reed <span dir="ltr"><<a href="mailto:peter.reed@aligre.co.uk">peter.reed@aligre.co.uk</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div lang="EN-GB" link="blue" vlink="purple">
<div>
<p class="MsoNormal">It’s been three months since I last tried to measure
road lengths on OSM against the Department for Transport statistics, and I
thought there might be some interest in how things are progressing. </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">At the moment this has only been updated where I already
have decent admin boundaries from OSM. In other words I’ve updated the
figures for all of England and some bits of Wales. </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">There are long complicated technical reasons (i.e. typing
errors) that mean the figures for Scotland and the rest of Wales still date
from January.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">In the updated areas I reckon that the length of roads in
the OSM database has increased by around 2% in the last three months so the
overall pattern of coverage stays much the same.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">The DfT reckons that there are about 343,000 km of road in
the areas I’ve updated – and I reckon 78% of them are on OSM.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">The most significant increases have been in: Stoke-on-Trent
(43% more roads), Luton (26%), Bolton (18%), and Redcar & Cleveland (16%).</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Another eleven local authority areas have seen the length of
roads on OSM increase by more than 10% (Vale of Glamorgan, Walsall, Poole, Northumberland,
Stockton-on-Tees, Bournemouth, Staffordshire, Dudley, North East Lincolnshire, Medway
and Dorset).</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Comparing different road types, it looks as though virtually
all major roads are covered; and about 72% of minor roads. </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">The actual numbers are:</p>
<p class="MsoNormal"> </p>
<p><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span>Motorways: DfT say 6,381 km, OSM contains
5,994 km, plus 1,093 km of link roads that the DfT tell me they don’t
count. Those numbers suggest that the DfT are really counting some roads that
are tagged as “motorway link” in OSM, but not all of them</p>
<p><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span>Primary: DfT says 43,356km, OSM contains 42,861km
= 99% mapped (there are variations from authority to authority)</p>
<p><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span>Secondary: DfT says 22,625km, OSM contains
22,549 km, = 100% mapped (there are variations from authority to authority)</p>
<p><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span>Tertiary: DfT says 73,878 km, OSM contains 33,547
km = 45% mapped</p>
<p><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span>Unclassified / residential: DfT says 196,681 km,
OSM contains 161,598 km = 82% mapped</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">That suggests to me that there is a tendency to tag roads
that DFT consider tertiary as unclassified / residential. No surprise there.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I should get round to extending the figures into Scotland
and the rest of Wales over the next couple of days. Meanwhile I hope this is of
some use, albeit as work in progress.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">The detailed breakdown is here – <a href="http://www.reedhome.org.uk/Documents/OSMCoverMar2010.csv" target="_blank">http://www.reedhome.org.uk/Documents/OSMCoverMar2010.csv</a>
</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">And there is a map here – <a href="http://www.reedhome.org.uk/Documents/OSMCoverMar2010.png" target="_blank">http://www.reedhome.org.uk/Documents/OSMCoverMar2010.png</a>
</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
</div>
</div>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Dr. Graham Jones<br>Hartlepool, UK<br>email: <a href="mailto:grahamjones139@gmail.com">grahamjones139@gmail.com</a><br>
</div>