1:25,000 maps

The second article in this set discusses the history of Ordnance Survey maps at the 1;25,000 scale, the scale preferred by ramblers and hill walkers.

Why they are my favourite OS map
I have always liked these maps best. They have the right combination of large scale and geographical coverage. They show stylistic developments, and reflect the changing social geography of an area in fascinating detail.

The Provisional Edition and the First Series
The 1:25,000 map was a new scale for the OS, and bridged the gap between the One-inch and Six-inch scales. The earliest of them started to appear in the mid-1940s.

The original name for these maps was the Provisional Edition. By the early 1950s, they were renamed the First Series. They always had blue covers. The edition letters show that the Provisional Edition and First Series belong to the same series, but the Provisional Edition was distinct because of:

• its ‘Six-inch’ styling, including buildings filled in by hatching, rather than the later solid olive green, and the many road names shown in towns.
• being mounted on cloth (usually).

These maps not only resembled the Six-inch maps in style. They showed much the same detail.  But they had the advantage that they covered a much larger area - a 10km² square - 100km² - four times as much. The colour scheme was simple - black, grey, blue, green and orange - and it lasted for the next 50 years, into the first of the Explorer series.

Some First Series maps exist which were a little more colourful, chiefly because the woodland was coloured bright green. These maps also experimented with other things, such as simplified building detail in built-up areas, black lines for field boundaries, and a different way of showing double-track railway lines. Overall these changes made the map clearer. But I have seen examples only from the West Country. Those were published from 1959.

The Second Series
In the 1970s the Second Series maps started to appear. These always had green covers, and were completely redrawn, with new lettering, and a little more colour, woodland being shown in pale green.  But the most important feature about the Second Series was that most sheets covered a 20km × 10km rectangle - 200km² - twice the area of the typical First Series map.  

The new maps looked much more ‘modern’. But in certain respects they were harder to read than the First Series, as the minor place names were smaller, and there was too much detail (and too little colouring) in urban areas. The maps were somewhat hard on the eyes, though perfectly clear if a magnifying glass were used. Not all sheets were drawn in the new style: some were simply First Series sheets with Second Series colouring. In some parts of the country this First Series appearance lingered on into the 1990s.

The Pathfinder edition
It took years for the old First Series maps to be completely replaced by the Second Series. The process was barely over, when, in the late 1970s, the old sheet numbers (based on the grid co-ordinates of the double-square covered) were abandoned, and replaced by a simple numerical sequence running from 1 to 1372. This sequence belonged to the Pathfinder edition. It was not, however, a new series - the edition letters show that Pathfinder maps were just a continuation of the Second Series, using the same sheet lines as before.

At some point in the 1970s the future of the 1:25,000 map was threatened. The government was anxious to save money, and put pressure on the OS. It took a good deal of lobbying from The Ramblers' Association and other user groups to save the map. Thank goodness they succeeded! For the detailed 1:25,000 map was going to have a bright future in the decades to come, with outdoor pursuits proliferating, and the topography of the country in any case becoming more crowded, and harder to depict clearly and accurately at the smaller 1:50,000 scale.

The Explorer series
In the early 1990s a new series appeared - the Explorer series. These covered a much larger area than the Second/Pathfinder series, typically 30km × 20 km - 600km² - three times the size of a Pathfinder map; or six times the area of a First Series map. Some sheets were double-sided, typically 20km × 20km on each side. The cover colour was now changed to orange. The sheet lines were completely new, intentionally fitting the map in the best way to cities and geographical features. You no longer had to buy a map on strict grid sheet lines, at full price, showing just one little island offshore, or just the furthest tip of a headland. Or two maps, each showing only one half of a big town or city. Such inconveniences were mostly swept away.

At first there were only a few sheets. They were in the Pathfinder style, but with a lot of tourist information in blue. The Explorer maps were originally intended to supplement the well-established 1:25,000 Outdoor Leisure maps (a development from the One-inch Tourist maps), which had distinctive yellow covers. Like the Outdoor Leisure maps, the first 30-odd Explorer sheets were numbered in the order they were published. Then the OS decided to extend coverage to every part of the country. The existing sheets were renumbered again to blend into a nationwide sequence running from 101 to 470, and more colours were used, so that in style the ‘new’ Explorer maps somewhat resembled the 1:50,000 Landranger maps. But they were of course much more detailed. The bright colours did much to make the denser detail clear. In 2002 the two kinds of 1:25,000 map were brought closer together, sharing a common cover design, the Outdoor Leisure maps being distinguished only by a yellow marking on the otherwise orange cover, and by using sheet numbers in the 1 to 100 range.

As with the Second/Pathfinder series before it, the publication of Explorer series sheets took several years, and was not complete until the end of 2003.

In 2004, the status and usefulness of these maps was enhanced by their showing Access Land - private and common land where the public could roam freely. The details appeared first on Explorer maps in south east and north west England. At around the same time, a waterproof edition (eventually called an Active Map) began to appear for certain areas. This was typically twice the price of the ordinary paper map, but it was certainly weatherproof and a boon to serious walkers. In a downpour it was easier and less risky to use a waterproof map than any electronic device. And such a map couldn't run out of battery power.

During the 2000s downloadable digital mapping for the general public took off. First you could buy Explorer mapping for a National Park, then later on for any user-defined area. Such maps could be displayed on a PC, laptop or (more portably) on a phone or tablet. Digital mapping had its obvious advantages, but it did not kill off sales of paper maps, any more than ebooks had killed sales of paper books. Paper maps showed a much larger area than any screen could - important for route-planning - and were essential as a backup, in case of mobile device loss, damage or failure, or if power ran out, or if signal reception were poor. But clearly the future lay mostly with the electronic version.

It was widely thought that one day the shop-bought paper map, with a sheet number, covering a fixed area, might be a thing of the past. Sales did reduce a little; but the paper map was not dead by any means.

From 2015 the paper 1:25,000 Explorer map is now being sold with a option to download an identical digital version, at no extra cost. Capable of magnification when viewed on a mobile device, the digital version has the same appearance and viewing resolution as the paper map itself. This innovation has given the user the best of both worlds: a digital map on familiar Explorer sheet lines. The Explorer series is the first type of paper map to come with this option. In 2015 the cost of the 1:25,000 paper/digital map - covering (typically) 20km x 30km = 600 km² and priced at £8.99 in High Street shops - is £0.015 per square kilometre. It looks like this on the phone:

It is also now possible, as a quite separate online-shop alternative, to buy and download a high-resolution (i.e. capable of greater magnification) 1:25,000 digital-only map covering 10km x 10km = 100km² for £1.99 - which works out at £0.02 per square kilometre. (For some coastal squares, it is only £1.49, or £0.015 per square kilometre, the same as for the paper/digital map) Each square of the digital-only map covers the same geographical area as a First Series paper map would have, and (how nostalgic this is!) has the same alphanumerical 'name', based upon the grid co-ordinates of the square - e.g. 'SW87' (which is the first digital square I have bought: it covers Trevose Head and Treyarnon Bay in Cornwall). It looks like this on the phone:

At present each kind of downloaded 1:25,000 digital map needs its own app for viewing - it isn't possible to merge the two kinds, and see one continuous map in the same app on one's phone, laptop or tablet. This suggests a certain buying strategy. For the home area, or at any rate for areas constantly visited and extensively explored, it seems best to buy the paper/digital map covering 600km², because all parts of it might be needed. It is also marginally cheaper in terms of cost per km². For areas only occasionally visited, or if the area of interest is very localised, the digital-only map seems the better choice.

For me, then, I would in the future go paper/digital for Sussex, North Devon and North Cornwall at £8.99 per map, acquiring 600km² each time, although there would often be some overlap at sheet edges. The rest of the country would be covered here and there with digital-only squares at £1.49 each, acquiring 100km² each time.

Everywhere else would be covered at a smaller scale by the digital 1:50,000 Landranger map, with smaller OS scales for route-planning. (In 2015, the OS are not yet offering an all-GB downloadable version of the 1:50,000 Landranger and 1:10,000 Streetview mapping - I still have to rely on Memory Map for this)

It is also possible to see maps online by paying an annual subscription to the OS. For the money (£17.95 in 2015, but likely to rise) one acquires unlimited viewing and printing rights - but without ever actually 'owning' a map. I don't find this option attractive.