Re: [Talk-GB] Estimating coverage
Peter Reed wrote: Interesting point from Paul (southglos) about slip roads. I’ve just worked the numbers slightly differently and he seems to be right. Adding up the total length of motorways in England according to DfT it comes to 6,021km. My total from OSM for England = 6,962km On face value we have found 900km of motorways that the DfT have lost. However if I break down the tags that make up my 6,962 km, it comes to 5,912 km tagged “motorway” and 1049 km tagged “motorway_link”. 5,912 km of “motorway” on OSM compared to 6,021km known to the DfT looks astonishingly close to me. What do you think – should I be ignoring “motoway_link” in the totals, counting it as something else (and if so what?), do we just put this down to the way DfT count the numbers, or is it just coincidence that the “motorway” numbers are so close? Can you ask them? A FoIA request might clarify the situation. Cheers, Chris ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Estimating coverage
Nick Austin wrote: > There are marker posts every 100 yards alongside the hard shoulder of all > motorways. I don't think slip roads have marker posts so if the DfT are > calculating distance by counting the marker posts then excluding slip > roads sounds a reasonable thing to do. > > Nick Pedant mode on There are marker posts on (some) slip roads, but they use the same distance as on the main carriageway iirc, just a different letter, to distinguish them Pedant mode off Jeni ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Estimating coverage
On Tue, Aug 11, 2009 at 8:07 PM, Peter Reed wrote: > What do you think – should I be ignoring “motoway_link” in the totals, > counting it as something else (and if so what?), do we just put this down to > the way DfT count the numbers, or is it just coincidence that the “motorway” > numbers are so close? There are marker posts every 100 yards alongside the hard shoulder of all motorways. I don't think slip roads have marker posts so if the DfT are calculating distance by counting the marker posts then excluding slip roads sounds a reasonable thing to do. Nick. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Estimating coverage
Interesting point from Paul (southglos) about slip roads. I've just worked the numbers slightly differently and he seems to be right. Adding up the total length of motorways in England according to DfT it comes to 6,021km. My total from OSM for England = 6,962km On face value we have found 900km of motorways that the DfT have lost. However if I break down the tags that make up my 6,962 km, it comes to 5,912 km tagged "motorway" and 1049 km tagged "motorway_link". 5,912 km of "motorway" on OSM compared to 6,021km known to the DfT looks astonishingly close to me. What do you think - should I be ignoring "motoway_link" in the totals, counting it as something else (and if so what?), do we just put this down to the way DfT count the numbers, or is it just coincidence that the "motorway" numbers are so close? ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
[Talk-GB] Mapzen Community Panel
Hi there, We’re looking for OSMers of all abilities to take part in an early hands-on preview session of Mapzen, CloudMade’s new OSM editor. As an early tester of Mapzen, you get to try out new features before anyone else and most importantly, get to make your mark on a new OSM editor. The testing sessions will take place in London during the week of the 17th August and Menlow Park, CA the week of the 24th August You can find out more about taking part in hands-on tests and about joining the Mapzen Community Panel in this blog post: http://community.cloudmade.com/join_mapzen_panel.html Thanks & hope to see you during a testing session soon Mapzen – http://wiki.openstreetmap.org/wiki/Mapzen ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Estimating coverage
>The area figures are obviously including the wet bits. Bristol is half >water: http://news.bbc.co.uk/1/hi/england/bristol/7019663.stm This article mentions Denny Island - which was absent from OSM. I've now added it from the NPE map, although I don't know whether its location has changed with the movement of the sands/mud. Does anyone have a more up to date source for its outline? Donald ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Estimating coverage
Hi Nice work! The area figures are obviously including the wet bits. Bristol is half water: http://news.bbc.co.uk/1/hi/england/bristol/7019663.stm I also notice the OSM motorway figures are generally a fair bit above the official figures - slip roads? Cheers Paul (southglos) -Original Message- Date: Tue, 11 Aug 2009 10:55:31 +0100 From: "Peter Reed" Subject: [Talk-GB] Estimating coverage I thought that comparing the area enclosed by the admin boundary on OSM with the area published by national statistics would be a good indicator of whether the boundary was accurate. In practice it works sometimes, but not others. I think this is mainly because of how the coastline and estuaries are handled in different places. Bristol is the extreme -the government thinks it is about twice as big as the area included in the boundary on OSM. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
[Talk-GB] Estimating coverage
I have now uploaded a summary of the figures for the UK coverage estimates as a CSV file here - http://www.reedhome.org.uk/Documents/OSMCoverage.csv Several people have expressed an interest in seeing the proportion of named roads by local authority area. Those figures are included in the table. There is also a map here - http://www.reedhome.org.uk/Documents/OSMNamed.png The other figure that may be of interest is the proportion of roads that have been plotted, but not completely tagged. See the column labelled "Percent other" in the CSV file. These roads are not included in my totals, because I can't tell what type they are. Broadly speaking these are roads marked as "highway" with a type of "road" or "fixme". There are also a few that have been mis-tagged, for example as or with a combination of conflicting highway types. But these are a very small proportion of the total. Most are tagged which is normally intended to mean "I know this road is here, but I have not yet decided what type it is". The overall proportion of these is quite low, but it is surprisingly high in some areas - notably Luton, and Northumberland for example, where almost a third of roads that have been plotted are not fully tagged with a type. Lincolnshire, Suffolk, Somerset, Trafford, Norfolk and Wiltshire also show a high proportion (>10%) of roads that I can't classify. I thought that comparing the area enclosed by the admin boundary on OSM with the area published by national statistics would be a good indicator of whether the boundary was accurate. In practice it works sometimes, but not others. I think this is mainly because of how the coastline and estuaries are handled in different places. Bristol is the extreme -the government thinks it is about twice as big as the area included in the boundary on OSM. The CSV file also shows the breakdown between different types of road (motorways, primary, secondary, etc). I've not looked closely at this yet, but a quick scan suggest that the figures for primary roads and motorways could sometimes be a good indicator of how accurate a boundary is. For example, it looks as though the boundary for Luton on OSM includes a bigger chunk of the M1 than the DfT believes they are responsible for. Enjoy. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Progress on estimating coverage
Shaun McDonald wrote: > It would be interesting to see the same charts taking into account the > nonames, to take into account the places that have been traced but not > yet named. +1 Emilie Laffray signature.asc Description: OpenPGP digital signature ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Wales Boundaries (Wrexham & Denbighshire)
On 11 Aug 2009, at 08:31, Peter Miller wrote:
>
> On 11 Aug 2009, at 07:43, Shaun McDonald wrote:
>
>>
>> On 11 Aug 2009, at 06:41, Peter Miller wrote:
>>
>>>
>>> On 10 Aug 2009, at 23:09, Bogus Zaba wrote:
>>>
With Denbighshire however I made a new relation (192442) and am
slowly
adding various ways that will make up this boundary. Not sure
however
how to edit the Denbighshire entry in the wiki to add the links
to the
way and the various analysis tools (b a r j links). Can someone
point me
in the right direction to do this.
>>>
>>> Open the wiki in edit and you will see the format which is
>>> {{BrowseRelation|xx}} where xx is the boundary relation
>>> number. Do add these to the wiki for any boundaries that have been
>>> started but not yet finished.
>>
>> Why should boundaries that are not yet complete not be added to the
>> wiki? Surely it would be better to have them there, just with the
>> status marked as not complete. It also means that is someone is
>> looking to continue the work of someone else then they can use that
>> information in the wiki.
>
> I completely agree, and I think that is what I said!
Gah, I should re-read things before responding. For some reason I read
it as Do not add these
>
> To be clear, I suggest that we all boundaries, ones in progress and
> ones that are complete to the wiki pages for England, Wales and
> Scotland. Someone does however need to create the relevant section
> on the Scotland page and list the administrative areas as well.
+1
Shaun
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Re: [Talk-GB] Wales Boundaries (Wrexham & Denbighshire)
On 11 Aug 2009, at 07:43, Shaun McDonald wrote:
>
> On 11 Aug 2009, at 06:41, Peter Miller wrote:
>
>>
>> On 10 Aug 2009, at 23:09, Bogus Zaba wrote:
>>
>>>
>>> With Denbighshire however I made a new relation (192442) and am
>>> slowly
>>> adding various ways that will make up this boundary. Not sure
>>> however
>>> how to edit the Denbighshire entry in the wiki to add the links to
>>> the
>>> way and the various analysis tools (b a r j links). Can someone
>>> point me
>>> in the right direction to do this.
>>
>> Open the wiki in edit and you will see the format which is
>> {{BrowseRelation|xx}} where xx is the boundary relation
>> number. Do add these to the wiki for any boundaries that have been
>> started but not yet finished.
>
> Why should boundaries that are not yet complete not be added to the
> wiki? Surely it would be better to have them there, just with the
> status marked as not complete. It also means that is someone is
> looking to continue the work of someone else then they can use that
> information in the wiki.
I completely agree, and I think that is what I said!
To be clear, I suggest that we all boundaries, ones in progress and
ones that are complete to the wiki pages for England, Wales and
Scotland. Someone does however need to create the relevant section on
the Scotland page and list the administrative areas as well.
Regards,
Peter
>
> Shaun
>
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