• Jamie

Choosing a map. (or why I use Harvey maps!)

There are a surprising amount of maps available in the UK with each type designed to exploit it's own activity niche. In this blog we'll just look at sheet maps used for walking on mountains and through the general outdoor environment.

All current UK maps use kilometre grid squares.

The three scales mainly used in Britain are 1:25, 1:50 and 1:40. On a 1:25 map, 1mm on the map is equal to 25m on the ground. On a 1:50 map, 1mm = 50m and on a 1:40 - 1mm = 40m.

There are two main brands in the UK - Ordnance Survey (OS) and Harvey and different people have different preferences for different situations. Each brand has it's own positives and negatives.

OS positives:

  • More contour detail.

  • More identifiable features

  • Complete UK coverage and ability to print off sections for anywhere necessary.

  • Can be easier for beginners.

  • Great for digital planning.

  • Rights of way through private land easily identifiable.

OS negatives:

  • Maps can be unclear in some environments.

  • Many paths are not shown on Scottish maps

  • Paper maps can be 'cut' to awkward areas, meaning you might have to carry multiple maps (take a look at Moel Siabod on OL17 Snowdon/Conwy for a perfect example)

  • Maps are not durable and waterproof does not hold up after much usage.

  • Bulky due to triple sheet laminated waterproof system.

  • Often have inaccuracies .

  • Paper maps need covers.

The unfortunate cutting of Moel Siabod

Harvey positives:

  • Clear and easy to read.

  • No unnecessary detail.

  • Logical area coverage.

  • Scottish mountains have more paths shown that are not on OS maps.

  • Lightweight & small.

  • Durable and waterproof owing to a single sheet polyethylene construction.

  • Accurate - each area is physically walked to check detail.

  • Climbing crags are identified.

  • Dangerous ground is more obvious.

  • 1:40 Harvey/BMC maps include a reverse sheet of local information about history/geology/mountain safety and enlarged sections of key mountains.

  • Specific long distance National Trail maps.

A compact 1:40 Harvey/BMC on the right.

Harvey negatives:

  • Don't have full UK coverage.

  • Less contour information.

  • Rights of way through private land not as obvious as OS.

  • Can take a bit of time to adjust after using OS maps.

Choosing a map is largely down to personal preference but there are a few considerations that could influence your choice.

An example of really clearly marked craggy ground, with climbing areas marked in red.
  • If you don't have good eyesight, 1:25 will be better than 1:50 as the grid squares are twice as big.

  • 1:25 maps are better for beginners.

  • 1:25 are easier to read in more complex terrain. (The beauty of Harvey/BMC 1:40 maps is that they include enlarged sections for key mountains)

  • If you are covering large distances, 1:50/1:40 might help you carry less maps. The same applies to wild camping, when you want to cut down on weight.

  • 1:50/1:40 maps are generally better for winter conditions where much of the detail on a 1:25 map, including contours, might be buried under snow.

It is good to get used to using different map scales. When I'm out in the mountains for my personal enjoyment I only really use Harvey maps now, unless I'm in an area they don't cover. I will usually carry both a 1:25 and a 1:40 BMC map. (It's good practice to carry a spare) If I'm practising micro navigation, I will use OS 1:25 maps and the same when i'm teaching beginners, though I'm questioning moving to Harvey maps for teaching too.

If you would like to join a map reading course focused on using Harvey maps, please subscribe to the website for upcoming group dates or send me an email. For anybody interested on booking onto a private course, you can choose whatever map you prefer. We can work through a selection of maps over one day or two or just stick to whatever your preference already is.

Ben Nevis Harvey Map
An enlarged section of Ben Nevis summit.

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