Map Reading - Preparation For Hillwalking
Map reading is an essential part of preparation. The commonly used OS map is the 1:50000 ie1.25"=1 mile although 1:25000 is also available showing more detail which is very useful for hillwalking preparation. The contours are at 10 metre intervals with a darker contour every 50 metres. The level above sea level is shown in metres with the numbers printed as one looks facing the slope. The closer together the contours the steeper the rise or drop. Rivers are shown in blue and are useful check points for location identification. Forests are shown in green but are subject to change and should not be relied upon for navigational purposes. It is of great benefit to study the map reading before any hillwalking under the magnifying glass to identify any features and obtain a better understanding of the scale of the environment on the ground. The blue grid lines help to identify the distances bearing in mind they are 1000 metres apart in both directions. If the grid is divided into 10 in both directions ie a 100 metre grid ,this is the easiest way to visualize the scale of the terrain you are crossing. This subsiduary grid forms the basis of the Grid Reference system where 6 figure references are used for pinpointing locations. This is accurate enough for 1:50000 scale maps, but the Global Positioning System uses 10 figure references for greater accuracy on more detailed maps. When identifying a reference point the vertical (Eastings) reading precedes the horizontal (Northings).
Navigation By Compass - Preparation For Hillwalking
The orienteering Compass is in two parts - the housing and the base plate. It should be at least 100mm (4in) long otherwise it will be difficult when following and taking bearings particularly on 1:25000 scale maps. The plastic transparent base plate contains a magnifying lense and the compass housing has a liquid filled capsule containing the magnetic needle. The red end is North seeking and the white end points South. The circumference is divided into180 segments of 2 degrees each with North, South, East, and West identified. Preparation For Hillwalking with Compass is much easier so it's good to take an advantage from it. On the base of the housing are a number of fine lines ,orienting lines with the central two joined to form an arrow . The point of the arrow lines up with the North position on the circumference. The sequence of operations in usage is as follows :- 1. Line the top edge of the base plate or the parallel lines along the proposed route with the direction arrow pointing to the target. 2. Rotate the housing so that the North arrow is pointing to the top of the map with the lines parallel with the grid lines running North to South. 3. Read off the degree bearing at the intersection of the arrow line on the base plate and the circumference of the hoiusing. 4. Add the magnetic variation noted on the top of the map (5 degrees 30 minutes in 1997) by rotating the housing . NB it changes by 9 minutes East per year. The Compass is now ready for use by holding it horizontal at chest height and turning until the red arrow on the housing lines up with the direction arrow on the base plate which is a great help while preparing for hillwalking. You now have a bearing between two known points but to estimate the distance travelled along that bearing one must know your stride distance. This is usually measured as the number of double strides per 100 metres. The average number is between 60 and 70. For example, a double stride of 1.5 metres(750 mm per stride) takes 66 to cover 100metres on flat ground. It is worth carrying pebbles or coins to reject every 100metres until a kilometre has been travelled or the distance to a change in direction point. This method is essential to master for hillwalking in mist but now the GPS can be used for the same purpose.
Route Planning - Preparation For Hillwalking
After studying the map in detail, prepare a route card, noting bearings at significant change in direction points. Work out the best stop points for "breaks", which should be taken away from summits in poor conditions eg. on the leeward side of the hill away from the prevailing wind. This point of hillwalking preparation is very important. One should eat little and often as a general rule and avoid gorging oneself just before a severe climb! Liquid intake is as important as food to combat the inevitable dehydration effects associated with the efforts involved. Remember about this during your hillwalking preparation. To estimate timings for walks, an average of 3 - 3.5 km / hr ie 1.75 - 2 miles/hour, which includes stops, should be allowed overall. On flat ground 4 - 5 km / hr ie. 2.5 - 3 miles / hour can be achieved. This quantifies as 12 - 15 minutes per kilometre. On not too steep ascents allow 1 minute for 10 metres rise but on very steep ascents this will double to 2 minutes per 10 metre ascent ie 1 hour per 1000ft. A copy of your route card should be left at home or with your temporary residence.