Contents: JohnThornMaps (UK and America)

What are John Thorn maps?
Key facts
Why might I want the John Thorn Map?
How to use a JohnThornMap

What are John Thorn maps?

John Thorn is an independent map maker. He has produced a topographic map of Britain which at its heart is OS mapping. It is a unique combination of Ordnance Survey Opendata and information from OpenStreetMap.

Included are Public Rights of Way, open access land for England and Wales and core paths in Scotland. Every building, road, railway, river, and wood known to the OS is on the map. The OSM data used includes footpaths, as well as other map features like pubs, toilets, airfields, abandoned railways, and viewpoints.

John has also made similarly detailed maps for America. I’ve not tried those but the samples in the Locus Map app look good.

Don’t be put off by John’s home made website. The Great Britain map is excellent.

JohnThornMaps key facts

Website	www.the-thorns.org.uk/mapping/walkers.html
View map online	Scotland only at WalkHighlands.co.uk
Map type	OS/OSM hybrid. (Vector and raster versions available).
Which devices?	Smartphone apps that import the mapsforge format. Garmin handhelds, watches and Basecamp software for computers.
File type and approx size for UK	1.8GB for the vector map of Great Britain (not Northern Ireland)
Cost	Approx £25 to keep forever.
Areas covered	Great Britain (and American maps are available too)
Contours, crags, ground, property boundaries.	OS Terrain 50 10m contours and OS 1:25k crag details. OSM ground detail. Field walls not marked.
Paths and tracks	A mix of OS PRoWs and OSM paths (in red).
Public Rights of Way and access land	PRoWs are coloured in green and purple. Access land is coloured yellow
Map styling	A fixed style. App may provide map and text magnification options.

Why might I want a John Thorn Map?

The JohnThornMap of Great Britain can be bought to keep forever for about £25. For less than the price of three OS paper sheets or a single years subscription to the OS Maps app, that is a bargain.

The OS data used includes OS ‘terrain 50’ contours (similar to those on a 1:50k OS map) and the same crag markings that are used on the 1:25k Explorer series. Consequently the terrain is accurately modelled.

If you’re someone who likes exploring the Scottish mountains then this map is a particularly good one to have on your devices. Many of the well-trodden paths on high ground are not marked on OS maps, even in honeypot areas like Glencoe. The JohnThornMap shows many of those paths as it adds OSM data to the OS crag/contour detail. See this popular Glencoe hotspot…

Designed with outdoor activity in mind and with so much OS data included you can be certain it’s a good map. The extra OSM paths and details that aren’t on the OS maps are a useful bonus.

Unlike converted paper OS maps, the vector map doesn’t fill up all the spare storage on your smartphone. The JohnThornMap of Great Britain requires about 1.8 GB on your phone. It looks sharper than a converted OS map and zooms well too. John can also supply raster versions of his map if your favourite app only imports raster mapping. Like converted OS paper maps, the raster versions require much more storage space. Vector’s best.

I don’t know of any other vector map which allows you to see the public rights of way, open access land, OS contours & crags, alongside OSM paths and other OSM information. The paths are brightly coloured so it’s obvious where they are. Green and purple for PRoWs and red for the rest. Open access land is obvious in yellow.

The OS opendata doesn’t provide property boundaries so the John Thorn map is missing walls around the farmland lower down in the valleys, however the paths through them are marked and it’s worth noting that the OS 1:50k maps don’t show these walls either. Some ground detail will be missing too. eg On a 1:25k OS map, marshy or stony ground may be shown.

Mapping from OsmAnd or OpenAndroMaps may contain many of those missing boundaries, as will the much more expensive OS Explorer mapping.

The John Thorn map has all you need to navigate safely. It is ideal for doing classic mountain routes like the Aonach Eagach ridge in Glencoe. A traverse of Liatach via the Am Fasarinen Pinnacles in Torridon or up to Ben Nevis via the famous Carn Mor Dearg arete.

These classic mountain routes thread their way through a lot of steep craggy ground. None of these paths are currently marked on the 1:25k OS mapping. They are all marked on the JohnThornMap which also has the same great crag detail supplied by the OS data.

It’s John’s maps which are currently being used by the WalkHighlands route planner. WalkHighlands also offers a free navigation app which downloads John’s mapping and the highlighted route for all the WalkHighlands routes. Very good.

How to use a JohnThornMap

Android smartphones
The vector map is available in the Locus Map 4 in-app Locus Store. That would be my choice. However, John Thorn can also supply vector map files for smartphone apps that will import the mapsforge file format. I’ve used it in Cartograph Maps and Oruxmaps. BackCountry Navigator Pro should work too.
WalkHighlands app : Good for the WalkHighlands routes in Scotland.

iPhones and iOS
Cartograph Maps uses the vector mapping offered on John’s website. I have tested it successfully.
WalkHighlands app : Good for the WalkHighlands routes in Scotland.

Raster version
If you have a phone app that will import the well-supported ‘sqlite’ file format that John generates, then you can use this version. I haven’t tested apps with this map as I prefer to use the vector map, which has a much smaller file size. Check out John’s website.

Garmins
There is a Garmin-compatible version for Garmin handhelds & watches, and installers for Garmin’s Basecamp desktop software too (Windows and macOS). Apart from the macOS desktop version, I’ve used all of these without issues and as I write they are all about £20.

If you have any queries, John offers an email address on his website. He’s been helpful when I’ve asked questions.