[Talk-GB] Use of PRoW Definitive Statements from Hertfordshire, Oxfordshire, Worcestershire

Robert Whittaker (OSM) robert.whittaker+osm at gmail.com
Thu Jun 21 23:55:48 BST 2012


I'm pleased to be able to report that three councils have agreed to
let us use their Definitive Statements of Public Rights of Way under
the UK Open Government License (OGL). (I'll be posting the emails I
sent to the councils and some other notes about the correspondence I
had with them in a separate message for anyone who's interested.) The
councils who've told me we can use their Definitive Statements under
the OGL are:

* Hertfordshire
* Oxfordshire
* Worcestershire

The first two of these have the statements online in a convenient form
[1], [2]. Worcestershire does not, but the text of each right of way
is available from a link in the popup by clicking on the interactive
map [3]. Accessing them in this way, it will be hard to avoid
inadvertently making use of the additional information about the route
of each way from the map. So I've obtained a list of all the image
files, which I'm planning to use to allow direct access to the
statements for each parish. Watch this space for more details, though
first I have to chase up a few of the files that seem to be missing.

The OGL requires attribution, so I've added details of these three
counties to the appropriate wiki page [4]. (Unfortunately though, this
page isn't obviously linked from the main OSM map or official
copyright/license page [5] so I'm not convinced that attribution
statements on [4] completely fulfil our obligations at the moment.
Yes, we've provided attribution, but it's not somewhere that we could
reasonably expect users to find it. I've been in touch with LWG about
this, and fixing things is on their to do list -- though it seem from
their minutes that this has been the case since September 2011. Does
anyone know who is able to edit the text on [5]?)

I'm hopeful that we'll be able to make use of the statements to verify
the designation of already mapped ways, and add the appropriate
designation tag where it's missing. In most cases, the description
probably won't be enough to be able to map a way without a survey.
However in conjunction with aerial imagery and maybe a bit of local
knowledge, it may be possible to do so for some routes. But the
statements will certainly be helpful in any effort of complete the
mapping of public rights of way by identifying missing routes in need
of a survey.

To help with matching routes up and checking off what has been found,
it will be useful to tag the ways with the Council's reference number,
using our ref=* key. Doing so has been discussed on this list before
[6]. (Though following some more recent discussion [7] we may be
heading towards using prow:ref=* instead to avoid a clash with other
uses of ref on the same ways.) In the thread at [6] it's been observed
that different councils use different path numbering schemes, so we'll
probably be unable to use a common scheme across the whole country.
Looking at the numbering scheme used by the three councils above, I'd
suggest the following ref formats:

* Hertfordshire: "[Parish] [0Num]"
* Oxfordshire: "[Pn]/[Num]"
* Worcestershire: "[PC]-[0Num]"

where [Parish] is the full parish name (in Title case), [Pn] is a
numerical parish code, [PC] is a two letter parish code (with
upper-case letters), [Num] is the numerical path number without
leading zeros, and [0Num] is the numerical path number with leading
zeros.

(Note that Worcestershire has re-numbered all their paths, giving each
segment between path junctions a distinct number within the parish.
The definitive statements still use the old numbers in the route
descriptions, and it might not be possible to tell which segment of
each route has which new number. It it probably a good idea to store
the original reference numbers in OSM too, eg with old_ref="[Parish]
[Num]" top make using the definitive statements easier.)

Finally, when tagging ways with designation=* and/or ref=* based on
the definitive statements, I think it would be useful to indicate the
source. I'd suggest using source:designation=definitive_statement
and/or source:ref=definitive_statement as appropriate.

Best wishes,

Robert.

[1] http://www.hertsdirect.org/services/envplan/countryside/walkingandriding/row/defmap/defstate/
[2] http://www.oxfordshire.gov.uk/cms/content/definitive-map-and-statement-online
[3] http://gis.worcestershire.gov.uk/website/Countryside/
[4] http://wiki.openstreetmap.org/wiki/Contributors#United_Kingdom
[5] http://www.openstreetmap.org/copyright
[6] Thread starts at
http://lists.openstreetmap.org/pipermail/talk-gb/2012-May/013314.html
[7] Thread starts at
http://lists.openstreetmap.org/pipermail/talk-gb/2012-June/013411.html

-- 
Robert Whittaker



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