Public Rights of Way Progress

Note that the "L_designation" lengths are only approximate (and will normally be an over-estimate) as the tool does not check precise parishes for ways with a designation tag but no prow_ref tag. Consequently, it includes any OSM ways of this type that fall within the rectangular boundaing box of each parish, rather than just those that are contained within the parish boundaries.

About this tool

This tool takes information about Public Rights of Way from four sources and flags up possible errors / omissions / things to check. Currently only a handful of counties are available, but hopefully more will be added in due course. The data sources are:

1. Official GIS data from County Councils. Many councils now have digital versions of the legal 'Definitive Map' document they are obliged to maintain. Many have made their data files available fir re-use under a suitable licence (see my open data page). Vector routes, path numbers, designations, lengths and bounding boxes can be extracted automatically from data files. I've started using the files from Barry Cornelius's rowmaps for this, as Barry has already done the hard work in converting the myriad of different formats from the councils into a standard KML format.
2. Volunteer-Mapped data from OpenStreetMap. Path numbers, designations, lengths, bounding boxes, last update details, etc. can be extracted automatically on a parish by parish basis using the XAPI. The tool will extract all ways with a prow_ref=* tag within the parish's bounding box. The data from OSM is updated on a rolling basis with each parish getting an update roughly once a week. There is a button at the bottom of each parish page to request a quicker update.
3. Definitive Statements. These are written documents providing textural descriptions of each Public Right of Way. Some councils have only paper records, but many now have digital versions. Sometimes these are unstructured formatted text documents (and so data needs to be manually extracted) but other councils have databases or spreadsheets (which allow automatic extraction of route numbers and statuses.
4. Manual classification of OSM completion level. This would be entered by tool users, after comparing the official data with the current mapping in OSM.

I've got scripts to do the extraction from first two sources set up, but I currently have to initiate the updates manually. I can do the third and fourth behind the scenes, but eventually the plan is to have a public Web interface.

With the data the tool can then flag up issues such as:

• Inconsistencies between the GIS data and Definitive Statements. (example)
• Overall progress with each parish, and RoWs missing / incomplete on OSM. (example)
• Various tagging errors in OSM. (some errors shown on parish pages)
• Possible incorrect completion levels based on a comparison of the OSM and GIS data. (example)
• Possible incorrect completion levels based on significant changes in either the OSM or GIS data since the completion level was last updated. (not implemented yet)

The tool is currently under development, so various key bits of functionality are not implemented yet. For details see the Known Issues and To Do List.

Suggested uses for OSM Mapping

• Identify places with unmapped rights of way, to then conduct a ground survey. (Please do not just add Rights of Way based on the GIS data from the Councils. This adds little benefit to OSM, and the alignment and accessibility may not be correct.)
• Identify Rights of Way that are mapped, but have incomplete or inaccurate tagging. For example, missing or incorrect designation=*, prow_ref=* or modal access tags. (See PRoW Tagging for recommendations.)
• Identify mapped routes that do not follow the official Definitive Line. These may need additional checking on the ground to verify if the Definitive Line is actually accessible or not.

However, please do not use the PRoW GIS data alone to map routes in OSM. The data may not be completely accurate or well-aligned, and it is important that we capture the physical presence and accessibility of routes on the ground too. Simply copying the Council's GIS data into OSM adds very little to the map. Correctly mapping a path with the condition of the surface, adjacent hedges, gates and stiles is much more useful. See also my advice for routes not following the definitive line.

Adding new authorities

I intend to add more areas as and when I have time to do so. The main constraints though are having access to the data and it being available for re-use under a suitable licence for use in OpenStreetMap. The basic requirements are:

• The council makes its Rights of Way GIS data available publicly. (A regularly updated file on their own website is preferred, though links on data.gov.uk or whatdotheyknow.com are ok too.)
• The council makes a public statement that the GIS data can be re-used under the Open Government Licence.
• The GIS data has been imported into rowmaps.com, so I can make use of its standard KML format.
• If the Council GIS data includes only reference numbers instead of parish names, then a lookup table is available that gives the parish name for each number.

It is also useful if the authority makes available its Definitive Statements, List of Streets and a list of Traffic Regulation Orders affecting Public Rights of Way. See my Council PRoW Open Data page for an incomplete list of what is available from each authority.