Composite mapping (OSM and OS, PRoWs etc)

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Composite mapping (OSM and OS, PRoWs etc)

Luke Smith
I mentioned a while back that grough was developing a composite map, blending OSM data with OS OpenData to fill in the gaps, and using public rights of way data directly from the local authorities which have released it. Over time, hopefully we will rely progressively less on other data sources.

I'm happy to say there's now a beta available, at http://geo.gy/ with more details about the project at http://map.grough.co.uk/

There'll also soon be a 3D version available, building on the prototype at http://3d.geo.gy/ to cover all of Great Britain and improve the controls.

The source code behind generating the maps is open source, although not suitable for on-the-fly tile generation because of the preprocessing. The idea was to create a map which could be printed and used at a fixed scale (1:25,000 scale), with labels moved around to avoid obscuring detail etc.

If anyone has comments or advice for us, it would be gratefully received. We're aware of some issues already, so this is only a beta release. Similarly if anyone would like to use the maps, we'd be more than happy to help if you run into problems.

Luke


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Re: Composite mapping (OSM and OS, PRoWs etc)

Dan S
Looking good! Is there a key? Would help to make sense of the various
footpath markings etc

Best
Dan

2016-09-06 8:02 GMT-07:00 Luke Smith <[hidden email]>:

> I mentioned a while back that grough was developing a composite map,
> blending OSM data with OS OpenData to fill in the gaps, and using public
> rights of way data directly from the local authorities which have released
> it. Over time, hopefully we will rely progressively less on other data
> sources.
>
> I'm happy to say there's now a beta available, at http://geo.gy/ with more
> details about the project at http://map.grough.co.uk/.
>
> There'll also soon be a 3D version available, building on the prototype at
> http://3d.geo.gy/ to cover all of Great Britain and improve the controls.
>
> The source code behind generating the maps is open source, although not
> suitable for on-the-fly tile generation because of the preprocessing. The
> idea was to create a map which could be printed and used at a fixed scale
> (1:25,000 scale), with labels moved around to avoid obscuring detail etc.
>
> If anyone has comments or advice for us, it would be gratefully received.
> We're aware of some issues already, so this is only a beta release.
> Similarly if anyone would like to use the maps, we'd be more than happy to
> help if you run into problems.
>
> Luke
>
>
> _______________________________________________
> Talk-GB mailing list
> [hidden email]
> https://lists.openstreetmap.org/listinfo/talk-gb
>

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Re: Composite mapping (OSM and OS, PRoWs etc)

Dave F
In reply to this post by Luke Smith
Looks very interesting. Has a bit of a 'Series 7' look to it, which I like.

Could you add a permalink, primarily so any specific queries/problems can be clearly identified?

It appears to render OS filed boundaries as grey short dashed lines. Is this intentional?

As a by-product of the PROW comparison, would it be possible to create a list (Geojson?) of paths not in OSM but in LA's definitive maps? It's something I always thought would be helpful to complete PROWS.

Looking forward to the full release.

Dave F. 

On 06/09/2016 16:02, Luke Smith wrote:
I mentioned a while back that grough was developing a composite map, blending OSM data with OS OpenData to fill in the gaps, and using public rights of way data directly from the local authorities which have released it. Over time, hopefully we will rely progressively less on other data sources.

I'm happy to say there's now a beta available, at http://geo.gy/ with more details about the project at http://map.grough.co.uk/

There'll also soon be a 3D version available, building on the prototype at http://3d.geo.gy/ to cover all of Great Britain and improve the controls.

The source code behind generating the maps is open source, although not suitable for on-the-fly tile generation because of the preprocessing. The idea was to create a map which could be printed and used at a fixed scale (1:25,000 scale), with labels moved around to avoid obscuring detail etc.

If anyone has comments or advice for us, it would be gratefully received. We're aware of some issues already, so this is only a beta release. Similarly if anyone would like to use the maps, we'd be more than happy to help if you run into problems.

Luke



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Re: Composite mapping (OSM and OS, PRoWs etc)

Robert Whittaker (OSM lists)
In reply to this post by Dan S
On 6 September 2016 at 16:53, Dan S <[hidden email]> wrote:
> Looking good! Is there a key? Would help to make sense of the various
> footpath markings etc

That does look really nice. I particularly like the long-distance
cycling and walking routes being shown. Maybe decrease the dot spacing
a bit at higher zooms though.

Are Public Rights of Way actually shown with specific markings,
separate from other paths/tracks with access tags set? I couldn't seem
to see anything obvious to distinguish them in the areas I just looked
at.

I noticed some some slight glitches in the road cartography caused by
the square ends of ways. Where a side road meets a main road at a
non-right-angle, you sometimes see a corner of the side road sticking
out on the other side of the main road.

Feature request: it would be nice to have a way to output the full
grid reference of a location on the map. Perhaps have a continuously
updated grid reference in one corner displaying the current location
of the mouse, and allow it to be frozen (for copying) by a single
click.

Best wishes,

Robert.

--
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Re: Composite mapping (OSM and OS, PRoWs etc)

Robert Whittaker (OSM lists)
In reply to this post by Dave F
On 6 September 2016 at 18:22, Dave F <[hidden email]> wrote:
> As a by-product of the PROW comparison, would it be possible to create a
> list (Geojson?) of paths not in OSM but in LA's definitive maps? It's

I don't know if you've seen it, but I've had a go at developing a
comparison tool for PRoWs myself:
http://robert.mathmos.net/osm/prow/progress/

The tool currently only covers Norfolk and Suffolk, but it could be
extended further afield if suitably licensed and formatted data is
available. There are also several missing features (in particular the
ability for anyone other than me to update the mapping completion
status of each route in the tool). But hopefully it's still useful to
people in it's current state. Other suggestions for improvements would
be welcome.

Robert.

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Re: Composite mapping (OSM and OS, PRoWs etc)

sk53.osm
I have done this on an ad hoc basis using QGIS but have never managed to transfer the process successfully to PostGIS.

I think Nick Whitlegg does this for his Android walking app with coverage of several counties in Southern England.

It's fundamentally much easier to show the difference than to convert that into suitable file formats (see the recent blog post about missing roads in Brazil which describes exactly this issue).

FWIW. What I do is :

  • Pull in the whole highway network from OSM
  • Buffer it by some magic number (10-25 metres)
  • Find all PRoWs which are within the buffers.
  • Repeat on last dataset for highways with designation tag.

Then one wants to do differences between all PROWS and PROWS matched to OSM & those lines and ones matched on designation.

I have a very crude mkgmap script which takes the output and draws thick lines in various colours as a transparent overlay for a Garmin device.

With PostGIS I have run into various problems including non-noded intersection errors in the latter steps. So I have never automated the process. However, for smallish data sets, e.g., all paths within 5-10 miles of a centroid (one can use Overpass to grab the data) it's quick enough to run the evening before venturing out.

Cheers,

Jerry

On 6 September 2016 at 18:46, Robert Whittaker (OSM lists) <[hidden email]> wrote:
On 6 September 2016 at 18:22, Dave F <[hidden email]> wrote:
> As a by-product of the PROW comparison, would it be possible to create a
> list (Geojson?) of paths not in OSM but in LA's definitive maps? It's

I don't know if you've seen it, but I've had a go at developing a
comparison tool for PRoWs myself:
http://robert.mathmos.net/osm/prow/progress/

The tool currently only covers Norfolk and Suffolk, but it could be
extended further afield if suitably licensed and formatted data is
available. There are also several missing features (in particular the
ability for anyone other than me to update the mapping completion
status of each route in the tool). But hopefully it's still useful to
people in it's current state. Other suggestions for improvements would
be welcome.

Robert.

--
Robert Whittaker

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Re: Composite mapping (OSM and OS, PRoWs etc)

Richard Fairhurst
In reply to this post by Luke Smith
Luke Smith wrote:
> If anyone has comments or advice for us, it would be gratefully received.

This is terrific. I've been waiting to see what you do with this since you first posted some sample images in 2011, so it's good to see it finally come to fruition. Lovely clear cartography and a convincing collection of source data.

The major thing you need to look at, I would suggest, is access tagging. At present you are showing (for example) private service roads the same as public service roads, which is obviously a bit of a problem for a map marketed to walkers. highway=path, access=private is also shown in a sufficiently bold style to mislead people that they can walk there.

The way that I solve this for http://cycle.travel/map is to use osm2pgsql's Lua processing to interpret the many possible access tag values. It takes a bit of persistence to get all the edge cases but I find it much easier than writing all the possible combinations into the SQL or CartoCSS.

Richard
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Re: Composite mapping (OSM and OS, PRoWs etc)

Paul Berry
In reply to this post by Luke Smith
Luke,

First impressions are that it's a thing of beauty and, for anyone enamoured of OS Pathfinder and Landranger styles, very easy on the eye. Hedges and walls as dashed lines are a little strange as such representations are ingrained in the mind as "paths" but otherwise I can't find fault at present.

It's a great effort; please keep at it!

Regards,
Paul


On 6 September 2016 at 16:02, Luke Smith <[hidden email]> wrote:
I mentioned a while back that grough was developing a composite map, blending OSM data with OS OpenData to fill in the gaps, and using public rights of way data directly from the local authorities which have released it. Over time, hopefully we will rely progressively less on other data sources.

I'm happy to say there's now a beta available, at http://geo.gy/ with more details about the project at http://map.grough.co.uk/

There'll also soon be a 3D version available, building on the prototype at http://3d.geo.gy/ to cover all of Great Britain and improve the controls.

The source code behind generating the maps is open source, although not suitable for on-the-fly tile generation because of the preprocessing. The idea was to create a map which could be printed and used at a fixed scale (1:25,000 scale), with labels moved around to avoid obscuring detail etc.

If anyone has comments or advice for us, it would be gratefully received. We're aware of some issues already, so this is only a beta release. Similarly if anyone would like to use the maps, we'd be more than happy to help if you run into problems.

Luke


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Re: Composite mapping (OSM and OS, PRoWs etc)

sk53.osm
In reply to this post by Richard Fairhurst
Can I add my enthusiasm for this style to that of Richard.

Some detailed points about the cartography, with examples taken from around Capel in Surrey (TQ1740 for quick reference):
  • Hedges & other barriers. I, like a couple of other commentators, find pecked lines a little confusing and perhaps a little too strong in comparison with the path elements. As these are only partially mapped on OSM they can be difficult to interpret as they stand. For instance in this part of Carthmarthenshire (SN4818) I mapped many hedgerows, but practical footpaths are more or less non-existent.
  • Churches in villages. A footpath goes through the churchyard in Capel. The War Memorial is shown, but the church is not. Unfortunately I don't think we ever adopted a tagging scheme which would allow spires & towers to be discriminated cartographically. (I realise this is a cartographic nightmare given the range of places of worship & density in towns, but they are highly useful orientation features in the countryside).
  • Access Land. Small narrow patches of access land dont show up very well. Compare the two areas in the village of Ockly (TQ1540). The northenmost patch is clear, but the southern patch in (TQ1539) is largely obscured by the roads. Similar issues can be seen along the N-S road in Walliswood to the SW. It may be that in this case familiarity will allow users to read these features just fine (I'm finding I recognise them easily now, but last nig t I was very much WTF are the brown splodges).
  • 10km grid lines. I'd like these slightly thicker than the 1km ones.

As for Richard's comment about access & LUA. Andy Townsend (SomeoneElse) has a LUA style which performs exactly those kind of transformations. https://github.com/SomeoneElseOSM/SomeoneElse-style. Of course it incorporates a lot of other stuff too.16

Although showing both OSM paths & official designations can result in some busyness I cant see any obvious alternative. The area around Ockley Station (TQ1640) shows several examples: path running S next to railway line (the official route obviously goes through someone's garden), further W a bridleway runs across an area of grassland in the official data but on the ground it goes round the edge (I looked twice). For the most part these discrepancies will be reduced or, in the future, we'll find a way to represent this either in OSM or elsewhere (for instance Robert Whittaker's PRoW tracking site).

Jerry Clough




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Re: Composite mapping (OSM and OS, PRoWs etc)

Ed Loach-2
In reply to this post by Luke Smith

I’m not sure which of your data sources give which bit of your rendering, but at about TM 151 312 (and I can’t get search by grid reference to find this location – slightly NE of Bradfield, Essex) you have both the correct route for the Essex Way (as in OSM, here-ish http://osm.org/go/0EHx9iB1-- ) where it has been diverted north and south of where it passes under the railway, and also show the pre-diverted footpaths (not in OSM) which used to cross the fields diagonally.

 

But generally I think it looks great.

 

Ed

 

PS: I just tried searching for the grid reference without spaces, and then it seemed to work.

 

From: Luke Smith [mailto:[hidden email]]
Sent: 06 September 2016 16:03
To: [hidden email]
Subject: [Talk-GB] Composite mapping (OSM and OS, PRoWs etc)

 

I mentioned a while back that grough was developing a composite map, blending OSM data with OS OpenData to fill in the gaps, and using public rights of way data directly from the local authorities which have released it. Over time, hopefully we will rely progressively less on other data sources.

 

I'm happy to say there's now a beta available, at http://geo.gy/ with more details about the project at http://map.grough.co.uk/

 

There'll also soon be a 3D version available, building on the prototype at http://3d.geo.gy/ to cover all of Great Britain and improve the controls.

 

The source code behind generating the maps is open source, although not suitable for on-the-fly tile generation because of the preprocessing. The idea was to create a map which could be printed and used at a fixed scale (1:25,000 scale), with labels moved around to avoid obscuring detail etc.

 

If anyone has comments or advice for us, it would be gratefully received. We're aware of some issues already, so this is only a beta release. Similarly if anyone would like to use the maps, we'd be more than happy to help if you run into problems.

 

Luke

 


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Re: Composite mapping (OSM and OS, PRoWs etc)

Luke Smith
First, let me thank you for all your comments. They’ve been very helpful indeed.

Second, let me apologise for the length of this reply.

Dan S:
> Looking good! Is there a key? Would help to make sense of the various
> footpath markings etc

Automating the legend was one of those jobs I kept putting off. I’ve just pushed an update that provides a basic legend; there’s still more to add. You can find the legend at http://geo.gy/legend/.

Robert Whittaker:
> That does look really nice. I particularly like the long-distance
> cycling and walking routes being shown. Maybe decrease the dot spacing
> a bit at higher zooms though.
> …
> Are Public Rights of Way actually shown with specific markings,
> separate from other paths/tracks with access tags set? I couldn't seem
> to see anything obvious to distinguish them in the areas I just looked
> at.
> …

Good points. A few people have mentioned the access markings, and it’s clear we need to rethink these. I will review these, and add new access categories that distinguish between a legal public right of way, and a maintained footway. I’ll also separate bridleways and cycle paths, add a category for Scottish core paths, and add permissive bridleways.

The current site is just intended as a way of accessing the maps for preview purposes. I’ll make the search accept place names shortly, and allow links to a specific grid reference. Using the History API I should be able to update the URL as you pan around the map, but I can also add a grid reference readout.

Dave F:
> Could you add a permalink, primarily so any specific queries/problems 
> can be clearly identified?

Sorry Dave, not sure what you mean? Do you mean the ability to link to a specific location on the map (lat/lon or grid ref)? If so sure, I’ll make that happen shortly.

> It appears to render OS filed boundaries as grey short dashed lines. Is 
> this intentional?

Yeah I appreciate the dashed lines are a bit odd. These aren’t actually taken from OS maps in the majority of cases. We processed the 2m LiDAR data from the EA and NRW, and used these to infer hedgerows and walls. Unfortunately as you noticed it’s not perfect, and worked better in some regions than others. I want to revisit this and try improve it by using their raw point cloud data.

In areas where OSM has field boundaries, the system throws away our LiDAR walls and uses OSM’s instead. The intention of the grey dashes was to suggest there’s a surface feature rather than definitely a wall, because from the LiDAR data we can’t be certain. I’ll come up with another way of showing them that’s less confusing.

> As a by-product of the PROW comparison, would it be possible to create a 
> list (Geojson?) of paths not in OSM but in LA's definitive maps? It's 
> something I always thought would be helpful to complete PROWS.

I’m happy to do whatever I can to help out in that respect, but Robert Whittaker’s system seems better suited. I don’t know if it’s helpful or not, but you’ll find the code I use for pulling in PRoW data in all sorts of different formats at [1], with some extra files for the awkward authorities that used numeric codes in their data etc. It pulls in the files then attempts to classify them automatically using common codes and abbreviations. Might help Robert keep his tool up to date?

SK53:
> With PostGIS I have run into various problems including non-noded
> intersection errors in the latter steps.

PostGIS and I now have a difficult relationship at best. Processing the whole country (with lots of ST_MakeValid calls and the like) to match all the PRoWs does take several hours. One thing we also do is try to deal with partial matches of the paths, so a new segment will be added only when OSM doesn’t already have a path stored, otherwise the legal status is updated instead. 

> Churches
Good point. I haven’t yet extended the building schema we use to accommodate ‘special’ buildings, but it’s on the plan. That would allow us to show a thicker border or different colour for significant buildings in a community, including churches. From a cartographic standpoint, there’s a system in place to prioritise some features, and aggregate features if they’re nearby into a single plural label. Churches would definitely be more helpful in navigation than memorials.

> Access land
I’ll look into this. The data from Natural England is a bit dodgy in places, with very very small gaps that can’t be shown on a 1:25,000 scale map. We remove some of the detail when we import it, but maybe we removed too much if these narrow patches are missing. One of the things I want to look at is moving features that are near to roads slightly.

> Grid lines
Good idea. I’ll make the 10km lines thicker.

> PRoWs through gardens and so on
Good points. My intention is to use OSM as the base for highways always, so if we match a local authority’s PRoW data against a path in OSM, the geometry will be taken from OSM and maybe we’ll indicate the discrepancy between the real path and the legal status in some other way.

Richard Fairhurst:
> The major thing you need to look at, I would suggest, is access tagging.

Absolutely. One thing I am concerned about is making it too complex (i.e. having to consult the legend all the time), but it’s clear we need to improve on the access tagging we have at the minute. Watch this space.

Paul Berry:
> It's a great effort; please keep at it!

Thanks – hopefully we’ll keep updating this once every few weeks. Unfortunately we can’t update as often as OSM does, because of all the data matching. 

Ed Loach:
> both the correct route for the Essex Way (as in OSM, here-ish http://osm.org/go/0EHx9iB1--
> where it has been diverted north and south of where it passes under the railway, and also show 
> the pre-diverted footpaths (not in OSM) which used to cross the fields diagonally

I’ll look into this. The official data I have downloaded might be old. Over time I want to move to also comparing timestamps on OSM updates, to deal with these changes more sensibly. The same issues likely apply to buildings, because OS OpenMap hasn’t been updated since 2015 so could have reinstated some demolished buildings.

> PS: I just tried searching for the grid reference without spaces, and then it seemed to work.

Oops. Fixed now.

Thanks once again for all your comments.

Cheers

Luke




On Wed, Sep 7, 2016 at 11:02 AM, Ed Loach <[hidden email]> wrote:

I’m not sure which of your data sources give which bit of your rendering, but at about TM 151 312 (and I can’t get search by grid reference to find this location – slightly NE of Bradfield, Essex) you have both the correct route for the Essex Way (as in OSM, here-ish http://osm.org/go/0EHx9iB1-- ) where it has been diverted north and south of where it passes under the railway, and also show the pre-diverted footpaths (not in OSM) which used to cross the fields diagonally.

 

But generally I think it looks great.

 

Ed

 

PS: I just tried searching for the grid reference without spaces, and then it seemed to work.

 

From: Luke Smith [mailto:[hidden email]]
Sent: 06 September 2016 16:03
To: [hidden email]
Subject: [Talk-GB] Composite mapping (OSM and OS, PRoWs etc)

 

I mentioned a while back that grough was developing a composite map, blending OSM data with OS OpenData to fill in the gaps, and using public rights of way data directly from the local authorities which have released it. Over time, hopefully we will rely progressively less on other data sources.

 

I'm happy to say there's now a beta available, at http://geo.gy/ with more details about the project at http://map.grough.co.uk/

 

There'll also soon be a 3D version available, building on the prototype at http://3d.geo.gy/ to cover all of Great Britain and improve the controls.

 

The source code behind generating the maps is open source, although not suitable for on-the-fly tile generation because of the preprocessing. The idea was to create a map which could be printed and used at a fixed scale (1:25,000 scale), with labels moved around to avoid obscuring detail etc.

 

If anyone has comments or advice for us, it would be gratefully received. We're aware of some issues already, so this is only a beta release. Similarly if anyone would like to use the maps, we'd be more than happy to help if you run into problems.

 

Luke

 




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Re: Composite mapping (OSM and OS, PRoWs etc)

sk53.osm

On 7 September 2016 at 15:29, Luke Smith <[hidden email]> wrote:
First, let me thank you for all your comments. They’ve been very helpful indeed.




Doh! Because I was looking at OSM in places where I'd mapped stuff (and then in the Peak District where Dudley has been mapping walls like mad) I hadn't realised that many of the linear features are Lidar-based.

We ought to look at that for OSM directly!

At smaller scales where these do show as lines it looks fine ,and very much better than OSM which introduces them too late for utility in countryside cartography for walkers.

With the Access Land a somewhat unconventional approach might be to place the border bleed on the outside of the area rather than inside. I cant think of any regular maps which do this, but I've found such 'halos' useful to pcik-out small features which would otherwise not be readily visible at smaller scales.

I must say I completely agree about the painfulness of PostGIS for this process of comparison. There must be a better way!

Jerry
 


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Re: Composite mapping (OSM and OS, PRoWs etc)

Dudley Ibbett
In reply to this post by Luke Smith

Hi Luke

It is a nice looking map you have produced.  As has been mentioned, I have put in quite a few of the field boundaries in the Peak District and have also tried to get the footpath network completely mapped over the last few years.  There are still a few to go but not many. 

I think others have already commented about marking PROW's along driveways etc.  You do get cases where footpaths go through a property but there is no access along the driveway to the property so it is good to have this detail.  To try and help with this I do try and add the designation tag and access=private tag where relevant.    I don't think this is universal practice and this style of tagging isn’t complete for the Peak District so you may have to rely on other data sources if you want to render PROWs along driveways etc.

Having looked at the map around the Peak District you may want to look at the rendering of quarries.  Whilst there is a label for these there seems to be no outline so I might currently think these were disused.   The outline of the quarry on OSM is sometimes the hole but can be cover the full operation.   Many quarries in the Peak District and probably other areas still have PROWs through them that still exist in the published PROW datasets and in theory will be put back or have been rerouted (permanently or temporarily).    You may want to give some priority to OSM footpath data in such areas as this is likely to be actually what is on the ground.

If a footpath isn’t accessible by a walker then I don’t generally put it on OSM or I will end it at the obstruction.  It looks like you are treating this as incomplete data and filling in the footpath according to the published PROW data.  Perhaps we need some way of tagging/putting these ways in OSM so they can potentially be eliminated when rendering a map that is designed to reflect footpaths that are accessible to walkers.


Kind Regards

  

Dudley





From: [hidden email]
Date: Tue, 6 Sep 2016 16:02:32 +0100
To: [hidden email]
Subject: [Talk-GB] Composite mapping (OSM and OS, PRoWs etc)

I mentioned a while back that grough was developing a composite map, blending OSM data with OS OpenData to fill in the gaps, and using public rights of way data directly from the local authorities which have released it. Over time, hopefully we will rely progressively less on other data sources.

I'm happy to say there's now a beta available, at http://geo.gy/ with more details about the project at http://map.grough.co.uk/

There'll also soon be a 3D version available, building on the prototype at http://3d.geo.gy/ to cover all of Great Britain and improve the controls.

The source code behind generating the maps is open source, although not suitable for on-the-fly tile generation because of the preprocessing. The idea was to create a map which could be printed and used at a fixed scale (1:25,000 scale), with labels moved around to avoid obscuring detail etc.

If anyone has comments or advice for us, it would be gratefully received. We're aware of some issues already, so this is only a beta release. Similarly if anyone would like to use the maps, we'd be more than happy to help if you run into problems.

Luke


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Re: Composite mapping (OSM and OS, PRoWs etc)

Robert Whittaker (OSM lists)
On 8 September 2016 at 20:56, Dudley Ibbett <[hidden email]> wrote:
> If a footpath isn’t accessible by a walker then I don’t generally put it on
> OSM or I will end it at the obstruction.  It looks like you are treating
> this as incomplete data and filling in the footpath according to the
> published PROW data.  Perhaps we need some way of tagging/putting these ways
> in OSM so they can potentially be eliminated when rendering a map that is
> designed to reflect footpaths that are accessible to walkers.

What I do in this case -- where I know where a PRoW route should go
from the Council data, and have surveyed it and found it inaccessible
-- is to add a way with appropriate designation=*, prow_ref=*, and
access tags (e.g. foot=designated), but also add highway=no and a
note=* to explain the situation. I believe this tagging is technically
accurate, as the mode-based access tags are supposed to be for legal,
rather than physical, access rights. However, the physical
inaccessibility isn't tagged explicitly in this scheme, and it would
be interesting to know what routers make of highway=no. (The
highway=no is used, as opposed to just not having a highway=* tag,
since a missing highway tag could arise from mapper error or because
the route hasn't been surveyed yet.)

I had a look to see if there were any physical equivalents of the
mode-based access tags (e.g. foot:physical=*, to mirror
maxheight:physical) but there didn't seem to be anything in use. I
haven't been using these tags so far, but perhaps it would be a good
idea to start. So for e.g. a Bridleway that's blocked by a hedge, you
could tag the short section through the hedge that's blocked as

designation=public_bridleway
prow_ref=Trumpton BR 5
foot=designated
horse=designated
bicycle=yes
highway=no
access:physical=no
note=Definitive line of PRoW but route here is completely blocked by hedge.

If the parts on either side of the hedge are accessible, then they can
be tagged as normal. If there's a in-use unofficial diversion, I'd tag
that with appropriate highway and access tags. (My understanding is
that legally you're allowed to circumnavigate any PRoW obstructions by
using a reasonable alternative on the same owner's land.)

Best wishes,

Robert.

--
Robert Whittaker

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Re: Composite mapping (OSM and OS, PRoWs etc)

Richard Fairhurst
Robert Whittaker (OSM lists) wrote:
> it would be interesting to know what routers make of highway=no.

From https://github.com/Project-OSRM/osrm-backend/blob/master/profiles/foot.lua:

  elseif access and access_tag_whitelist[access] then
      -- unknown way, but valid access tag
    result.forward_speed = walking_speed
    result.backward_speed = walking_speed

i.e. OSRM's foot profile will route over an unknown highway value if there is a valid access tag. (The bike profile is similar.) This isn't necessarily a bad thing - it's a fallback for old tags like highway=minor or highway=byway, and perhaps for typos too.

I'm not enormously comfortable with highway=no - it's a bit like the justly discouraged amenity=pub, disused=yes. The designation= tag should be enough on its own for something that isn't actually a highway on the ground. (Maybe one could invent a namespaced highway tag but I can't immediately think of anything suitable...)

cheers
Richard
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Re: Composite mapping (OSM and OS, PRoWs etc)

sk53.osm
On 9 September 2016 at 12:35, Richard Fairhurst <[hidden email]> wrote:
Robert Whittaker (OSM lists) wrote:
> it would be interesting to know what routers make of highway=no.

From
https://github.com/Project-OSRM/osrm-backend/blob/master/profiles/foot.lua:

  ...

I'm not enormously comfortable with highway=no - it's a bit like the justly
discouraged amenity=pub, disused=yes. The designation= tag should be enough
on its own for something that isn't actually a highway on the ground. (Maybe
one could invent a namespaced highway tag but I can't immediately think of
anything suitable...)

cheers
Richard



This is exactly what we did with this PRoW which is signposted but never used as the track round the edge of the field is more convenient: http://www.openstreetmap.org/way/293561685.

I was looking at  East & West Sussex council websites the other day (following up a note from a MapBox mapper) and they have lists of temporarily closed and obstructed PRoWs. If this type of information could be put into a common format (something like prow_ref, start GR, end GR, closure dates) and either provided by councils or crowd-sourced then this could be a useful way of identifying paths which ought not to be shown. Gating orders in towns are another consideration.

Fortunately Carmarthenshire haven't released their data: working out which footpaths are viable is a tough task for much of the authority's area.

Jerry


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Re: Composite mapping (OSM and OS, PRoWs etc)

Robert Whittaker (OSM lists)
In reply to this post by Richard Fairhurst
On 9 September 2016 at 12:35, Richard Fairhurst <[hidden email]> wrote:
> I'm not enormously comfortable with highway=no - it's a bit like the justly
> discouraged amenity=pub, disused=yes. The designation= tag should be enough
> on its own for something that isn't actually a highway on the ground. (Maybe
> one could invent a namespaced highway tag but I can't immediately think of
> anything suitable...)

I agree that it's not perfect, but I think there definitely needs to
be a way to tag something explicitly as "not a highway", for cases
where other tagging suggests that it would normally be one. In
particular, there should be a way to distinguish programatically
between a way whose highway type is unknown and one where it is known
not to be a highway. The first case could arise by a mapper
accidentally missing or mis-spelling the highway tag or a remote
mapper being unable to add a highway tag without a ground survey
(there are a number of these on PRoW in Norfolk). For either
alternative, tools might like to report such instances as errors or
warnings for further investigation, but they should be able to avoid
reporting ways that are known not to be highways and tagged as such in
an appropriate fashion.

Actually, as far as routing is concerned, having to deal with
highway=no is probably not too bad: highway=construction and
highway=proposed are presumably handled as special cases somehow, so
"no" could be dealt with in the same way.

Robert.

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Robert Whittaker

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Re: Composite mapping (OSM and OS, PRoWs etc)

Luke Smith
In reply to this post by sk53.osm
Dudley was quite right, if there's a section of path in the PRoW dataset our code would fill in the gap, on the assumption it was incomplete. If there's a clear logical way of indicating a legal right of way that can't be used in reality then I'll gladly update the code to reflect it. It's a difficult one, because in theory without a Public Path Order, the highway authority could turn up tomorrow and enforce the right of way, not that it happens often.

I understand most highway authorities have mailing lists for updates to public rights of way, which include interested parties on parish councils, Ordnance Survey and sometimes Harvey Maps etc. Because grough has a good working relationship with the Lake District NPA they offered to add us to theirs (though ironically, haven't published any PRoW opendata), but I was considering contacting other authorities and requesting to be added to any PRoW mailing lists they have. 

If successful in getting signed up to enough of these lists, we'd happily develop and maintain some sort of database for the information we receive, which might help keep track of new footpaths and diversion orders. Where footpaths have their references in OSM it should be trivial to find them. In other cases you'd need to consult the OS map accompanying the order. I'm not sure the authorities would consent to these being publicly accessible online, if they're not already.

Luke


On Fri, Sep 9, 2016 at 1:12 PM, SK53 <[hidden email]> wrote:
On 9 September 2016 at 12:35, Richard Fairhurst <[hidden email]> wrote:
Robert Whittaker (OSM lists) wrote:
> it would be interesting to know what routers make of highway=no.

From
https://github.com/Project-OSRM/osrm-backend/blob/master/profiles/foot.lua:

  ...

I'm not enormously comfortable with highway=no - it's a bit like the justly
discouraged amenity=pub, disused=yes. The designation= tag should be enough
on its own for something that isn't actually a highway on the ground. (Maybe
one could invent a namespaced highway tag but I can't immediately think of
anything suitable...)

cheers
Richard



This is exactly what we did with this PRoW which is signposted but never used as the track round the edge of the field is more convenient: http://www.openstreetmap.org/way/293561685.

I was looking at  East & West Sussex council websites the other day (following up a note from a MapBox mapper) and they have lists of temporarily closed and obstructed PRoWs. If this type of information could be put into a common format (something like prow_ref, start GR, end GR, closure dates) and either provided by councils or crowd-sourced then this could be a useful way of identifying paths which ought not to be shown. Gating orders in towns are another consideration.

Fortunately Carmarthenshire haven't released their data: working out which footpaths are viable is a tough task for much of the authority's area.

Jerry


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