Hello Bill,

I was playing around with the same idea a couple of years ago and developed a 
utility to segmentise OSM data:

https://trac.openstreetmap.org/browser/subversion/applications/utils/export/segmentise

I think it worked reasonably well.

Nick

-----Bill Chadwick <[email protected]> wrote: -----
To: "[email protected]" <[email protected]>
From: Bill Chadwick <[email protected]>
Date: 30/12/2012 10:53PM
Subject: [Talk-GB] Fwd: Footpath segmentation






Several UK local authorities have released their Public Right of Way data under 
a Open Data license
Barry Cornelius has been doing a great job of collating the data sets here

http://www.rowmaps.com/kmls/

I have been processing these into UTF Grids at Google Zooms 13-15 to use for 
route creation aiding on my hike/bike/... route planning site here

http://wtp2.appspot.com/wheresthepath.h … &oz=8&gt=1

Press the Wand button (top left tool bar rightmost) then the Route button 
(bottom left tool bar, leftmost). You can then click e.g. along the Thames path 
building the route you want. Off PROW points, e.g. along a road, are included 
if no PROW is highlighted when you click. The PROW assistance can be toggled on 
/ off at any time. On clicking a PROW it is linked to the existing route by its 
end nearest to the end of the route. When starting a route with a PROW, the end 
of the PROW nearest the click is used as the start. You can use use Right-Click 
to rub out route points from the end of the route. If you pick the wrong path.

Fortunately the released PROW data has a pretty good and consistent 
segmentation treatment with each path segment, between junctions with other 
paths and roads, being a separate feature.

As some of the honeypot counties like Cumbria have not (yet) released PROW 
data, I have been attempting to use OSM path data for those areas.

Unfortunately I find that the OSM path data has a wildly varying segmentation 
treatment. At Troutbeck, near to Windermere, you will find a very long path 
that goes all up Troutbeck, over Thornthwaite Crag, Froswick, Ill Bell and Yoke 
and then to the Garburn Pass. 
This path is OSM is way 27577503 in cumbria.osm from 
http://download.geofabrik.de/openstreet … n/england/ .  Such a long path is not 
very useful for off road routing as it has many junctions with other paths 
along its length. 
I have had to implement a simple segmentation algorithm before using the OSM 
path data for route aiding. You should be able to see the segmentation as you 
mouseover the above path on my test page here

http://ukprow.appspot.com/map/prow_test.htm

I would be interested to hear how council released prow data has / has not been 
used within OSM to add to or replace existing contributed path data. Hants and 
Devon have released PROW data but sadly many of the paths in the New Forest and 
Dartmoor are not PROW (black dashes on the OS 1:50K). It would be good to use a 
blend of OSM and council data in such areas but I am unsure how to avoid 
duplicate paths if there are paths in OSM not tagged as PROW.

Of course the best solution to all this would be for OS to release a national 
path data set as Open Data.

Bill Chadwick



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