Open Street map

Talk about items you find on SABRE Maps - interesting features, historic road layouts etc. Also contains announcements of new maps available on SABRE Maps.

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Alderpoint
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Re: Open Street map

Post by Alderpoint » Fri Feb 12, 2021 22:06

Let it snow.

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Stevie D
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Re: Open Street map

Post by Stevie D » Fri Feb 12, 2021 22:19

A42_Sparks wrote:
Fri Feb 12, 2021 20:26
In Northern Ireland there are three main mountainous areas: the Mournes, the Sperrins and the Antrim hills.

I've noticed on OpenStreetMap that the summit heights given for the Antrim hills are all wrong. They're all listed as being about 10%-12% higher than they are in reality. Here are some examples:

Trostan is 550m high but OSM says 603m.
Slievenanee 543m, OSM says 596m.
Slemish 437m, OSM says 490m.

I checked the Mournes and the Sperrins and the OSM summit heights are the same as the real heights. I don't know how to edit OSM myself to fix this issue but it needs fixing.
The note on the node for Trostan says "Irish summit data imported from mountainviews.ie", so that would be the first place to check.

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A42_Sparks
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Re: Open Street map

Post by A42_Sparks » Sat Feb 13, 2021 15:17

'In OSM, the same elevation is shown in the tag ele:local. But for some reason, the ele tag has an offset of 54 meters (in both cases you mentioned), and is the same as ele:wsg84.'

Thanks for that, it explains it. The hills are simply listed as being 53-54m higher than reality due to this offset.

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A42_Sparks
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Re: Open Street map

Post by A42_Sparks » Sat Feb 13, 2021 15:19

Stevie D wrote:
Fri Feb 12, 2021 22:19
The note on the node for Trostan says "Irish summit data imported from mountainviews.ie", so that would be the first place to check.
Alderpoint's post explained it. MV's data is correct - as it happens, I'm a member of that site.

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Re: Open Street map

Post by roadphotos » Sun Feb 14, 2021 14:31

The B1542 from Guyhirn to Wisbech (via Wisbech St Mary) is not shown on the Open Street Map. I was going to add it myself but the only evidence I have that it exists is the latest OS maps that show the B1542 on the route of what used to be a 'C Road'. Also the Open Street Map shows the B1166 at Wisbech St Mary which I believe is incorrect. As far as I am aware the B1166 ends at the B1169 and doesn't actually reach the village. Also does anyone know if the B1542 is signed on the ground.

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c2R
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Re: Open Street map

Post by c2R » Sun Feb 14, 2021 17:52

roadphotos wrote:
Sun Feb 14, 2021 14:31
The B1542 from Guyhirn to Wisbech (via Wisbech St Mary) is not shown on the Open Street Map. I was going to add it myself but the only evidence I have that it exists is the latest OS maps that show the B1542 on the route of what used to be a 'C Road'. Also the Open Street Map shows the B1166 at Wisbech St Mary which I believe is incorrect. As far as I am aware the B1166 ends at the B1169 and doesn't actually reach the village. Also does anyone know if the B1542 is signed on the ground.
All these changes (and the ending of the B1166 at Wisbech St Mary) appear on the latest version of Cambridgeshire County Council's interactive road list map.

I don't know what is signed on the ground (since lockdown,I've only been that way once for a funeral and it wasn't really therefore the time or the place to do some reconnaissance for SABRE) but updated the SABRE wiki based on the latest OS/CambsCC changes).
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roadphotos
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Re: Open Street map

Post by roadphotos » Sun Feb 14, 2021 20:34

Thanks, interesting about the B1166 as the latest online OS maps don't show this 'B Road' at Wisbech St Mary. They do show the B1542 in the village but it still shows the B1166 ending at the B1169. Also if the B1166 does indeed now end at Wisbech St Mary then the information on the Wiki will need updating.

roadphotos
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Re: Open Street map

Post by roadphotos » Sun Mar 07, 2021 12:13

A quick question, when a road on the OpenStreetMap is yellow does this mean that it's a 'B Road' or not. The key says that a road coloured yellow is a Secondary Road but I'm not sure exactly what this means. There are a lot of roads in and around the centre of Leeds that are shown coloured yellow on the OpenStreetMap even though there are no 'B Road's near the centre of the city. They are shown yellow with no road number. If yellow is supposed to be a 'B Road' then they would all be incorrect unless there's something that I'm missing with the term Secondary Road. I thought that I'd ask the question to see if anyone knows more.

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Re: Open Street map

Post by Stevie D » Sun Mar 07, 2021 16:24

roadphotos wrote:
Sun Mar 07, 2021 12:13
A quick question, when a road on the OpenStreetMap is yellow does this mean that it's a 'B Road' or not. The key says that a road coloured yellow is a Secondary Road but I'm not sure exactly what this means. There are a lot of roads in and around the centre of Leeds that are shown coloured yellow on the OpenStreetMap even though there are no 'B Road's near the centre of the city. They are shown yellow with no road number. If yellow is supposed to be a 'B Road' then they would all be incorrect unless there's something that I'm missing with the term Secondary Road. I thought that I'd ask the question to see if anyone knows more.
Yes, in the UK a secondary road is defined as a B-road.

It looks as though someone has corrected those roads in Leeds as they are now tagged as tertiary, although not all of the tiles have been updated at all mapping levels yet so it's still a bit inconsistent when viewing the maps.

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Re: Open Street map

Post by GC_NEMan1 » Sun Mar 07, 2021 18:09

roadphotos wrote:
Sun Mar 07, 2021 12:13
A quick question, when a road on the OpenStreetMap is yellow does this mean that it's a 'B Road' or not. The key says that a road coloured yellow is a Secondary Road but I'm not sure exactly what this means. There are a lot of roads in and around the centre of Leeds that are shown coloured yellow on the OpenStreetMap even though there are no 'B Road's near the centre of the city. They are shown yellow with no road number. If yellow is supposed to be a 'B Road' then they would all be incorrect unless there's something that I'm missing with the term Secondary Road. I thought that I'd ask the question to see if anyone knows more.
I would only use OpenStreetMap "Secondary Road" to refer to actual B-roads (if they don't have displayed numbers I'd use "Tertiary Road" instead), while I'd always refer to primary A-roads as "Trunk Road" as (in the past at least) those roads were displayed on the map in green.

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Stevie D
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Re: Open Street map

Post by Stevie D » Sun Mar 07, 2021 20:30

GC_NEMan1 wrote:
Sun Mar 07, 2021 18:09
I would only use OpenStreetMap "Secondary Road" to refer to actual B-roads (if they don't have displayed numbers I'd use "Tertiary Road" instead), while I'd always refer to primary A-roads as "Trunk Road" as (in the past at least) those roads were displayed on the map in green.
Yes, the guidance notes say that, in the UK
OSM Trunk = primary A road
OSM Primary = non-primary A-road
OSM Secondary = B-road
OSM Tertiary = significant unclassified road – typically those marked in amber on OS 1:25000 maps (although obviously you shouldn't use OS maps as source material, that gives you a guide as to the kind of road that should be tagged as tertiary).

In some countries, there is a clear hierarchy of official classifications that matches neatly into the OSM definitions, but not in all!

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Chris Bertram
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Re: Open Street map

Post by Chris Bertram » Sun Mar 07, 2021 23:01

Stevie D wrote:
Sun Mar 07, 2021 20:30
GC_NEMan1 wrote:
Sun Mar 07, 2021 18:09
I would only use OpenStreetMap "Secondary Road" to refer to actual B-roads (if they don't have displayed numbers I'd use "Tertiary Road" instead), while I'd always refer to primary A-roads as "Trunk Road" as (in the past at least) those roads were displayed on the map in green.
Yes, the guidance notes say that, in the UK
OSM Trunk = primary A road
OSM Primary = non-primary A-road
OSM Secondary = B-road
OSM Tertiary = significant unclassified road – typically those marked in amber on OS 1:25000 maps (although obviously you shouldn't use OS maps as source material, that gives you a guide as to the kind of road that should be tagged as tertiary).

In some countries, there is a clear hierarchy of official classifications that matches neatly into the OSM definitions, but not in all!
It would be lovely if Trunk meant Primary everywhere, which it doesn't, at least in England and Wales. But it's a nearest fit for OSM, so I guess we have to live with it.
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Re: Open Street map

Post by c2R » Mon Mar 08, 2021 08:58

It's still better than the Spanish system, which relies on who owns the roads to colour them in rather than actually looking at the roads and their purpose. There's any number of places where a locality has built its own bypass, while a regional or national road goes through the middle of town/village narrow streets and is subject to a weight or width restriction. As the regional or national road never appears to get downgraded or moved, one of the following two things occur:
* A trunk road appears from a motorway and heads through a village where about three people live before rejoining the motorway again in the other side of the village, thus implying it is a suitable diversion route, when it really may not be - this sort of thing: https://www.sabre-roads.org.uk/maps/ind ... 14&layer=0
* A trunk/primary/secondary road goes through the middle of a town, while a tertiary road has been built by the town to bypass it - https://www.sabre-roads.org.uk/maps/ind ... 16&layer=0

Clearly, this situation arises in Spain because of failures in their classification system and failures to 'trunk' and 'detrunk' roads from national and regional networks as appropriate - but it in my view makes a nonsense of OSM being useful for navigation in Spain. Although it is of course very useful for showing who owns what road....
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Stevie D
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Re: Open Street map

Post by Stevie D » Mon Mar 08, 2021 09:38

c2R wrote:
Mon Mar 08, 2021 08:58
It's still better than the Spanish system, which relies on who owns the roads to colour them in rather than actually looking at the roads and their purpose. There's any number of places where a locality has built its own bypass, while a regional or national road goes through the middle of town/village narrow streets and is subject to a weight or width restriction. As the regional or national road never appears to get downgraded or moved, one of the following two things occur:
* A trunk road appears from a motorway and heads through a village where about three people live before rejoining the motorway again in the other side of the village, thus implying it is a suitable diversion route, when it really may not be - this sort of thing: https://www.sabre-roads.org.uk/maps/ind ... 14&layer=0
* A trunk/primary/secondary road goes through the middle of a town, while a tertiary road has been built by the town to bypass it - https://www.sabre-roads.org.uk/maps/ind ... 16&layer=0

Clearly, this situation arises in Spain because of failures in their classification system and failures to 'trunk' and 'detrunk' roads from national and regional networks as appropriate - but it in my view makes a nonsense of OSM being useful for navigation in Spain. Although it is of course very useful for showing who owns what road....
That sort of thing used to be common in France 20 or 30 years ago, when smaller towns would often have a ring road or bypass that was marked as a lower standard than the main road through the centre-ville, and I think was often signed for light vehicles only although I may be wrong on that. Invariably it would involve a right angle turn at either end, rather than being a by-pass like we think of it where you stay on the main road to avoid the town, and turn off to go into it.

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Re: Open Street map

Post by Richard_Fairhurst » Mon Mar 08, 2021 21:06

c2R wrote:
Mon Mar 08, 2021 08:58
Clearly, this situation arises in Spain because of failures in their classification system and failures to 'trunk' and 'detrunk' roads from national and regional networks as appropriate - but it in my view makes a nonsense of OSM being useful for navigation in Spain. Although it is of course very useful for showing who owns what road....
Yeah, it's not great. The French OSM community have made a better job of their map.
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Re: Open Street map

Post by roadphotos » Sun Apr 04, 2021 10:58

The B1029 at Brightlingsea appears to be shown incorrectly on the OSM but I don't want to change it until I'm sure of the exact route of the B1029 through the town and where it ends. I believe that it ends by the riverside, does anyone know for sure ?. Also the OS Explorer map still shows the B1030 in Brightlingsea which I don't think is correct.

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