SCALE (CONT'D)

Paps of Jura

Road and Path Distances

To measure a distance, which is not straight, i,e, along a road, consider the road as a number of straight sections. lay a piece of paper along the first section, and mark it with a tick at the starting point and another at the end of the first section. Then pivot the paper about the tick until it lies along the second section, mark this end of the section with another tick and repeat the process until the last point is marked.

The total distance along the road or path is then recorded as a straight line on the paper. It can then be placed along the relevant scale at the bottom of the map to find out the distance.Either in statute miles,kilometres or nautical miles.

If this is done correctly it is surprising how accurate it can be.

Measuring Distances

Judging Distances

Grid Squares One method is by using the grid squares.

Experience Another way which comes with experience is by looking at the terrain and getting to know what size objects look at different distances.

Team Average All members of the team or party judge the distance to the objective, you then add all the totals together and then divide that total with the amount of team or party members.

Football Field Method Using this method you have to judge how many football field lengths you can fit in between you and your objective.

Points to Remember When Judging Distances

Dead Ground : This is an area of ground you cannot see, it could be a dip in the ground, sloping ground in front of you. or the area behind a hill, or wood. Basically any object or natural feature where you cannot see the ground behind it.

Other things to consider bad visibility and shadows especially at dawn and dusk

Football Field Method of Measuring Distance

Picture taken on Ardtornish Estate Loch Aline

Height Gained

Picture taken from path to the Cobbler

Knitting row counter attached to backpack

Pacing

You need to know how many double paces it takes you to cover 100 metres. The average person takes approximately 65 double paces.

By counting your paces as you walk, you can judge how far you have traveled. This is obviously useful for night navigation or in bad visibilty.

What you have to remember is that different types of terrain will effect your pacing, also going up and downhill.

A lot of people have different methods of recording every 100 metres they have travelled:

The method I use is cheap, simple and effective, a knitting row counter attached to one of the shoulder straps of my backpack.

FACTORS - AFFECTING PACE

Slope: Pace lengthens downhill, shortens uphill.
Winds: Tailwind will lengthen, headwinds will shorten.
Surface: Loose surfaces tend to shorten pace.
Equipment: Heavy burdens, shorter pace.
Stamina: Fatigue will shorten pace.
Visibility: Bad or at night will shorten the pace.

CALCULATIONS

Speed Time and Distance When planning any movement it is necessary to calculate time of arrival (eta), or, if the arrival time is pre-detemined, it is necessary to calculate and estimated time of departure (etd) which will ensure arrival at the time appointed.

The variables are thus speed, time and distance.

Speed              =                 Distance over Time

Time                =                 Distance over Speed

Distance         =                Speed x Time

Example:

If the road distance on the map equals 35 miles and the average speed for this type of road in a vehicle is 30mph. Then the time elapsed for this, as follows:

35 miles (Distance)

30 mph (Speed)

= 1hr 10min (Time)

Naismiths Rule

When calculating how long it will take to walk to a certain point remember this simple formula:

Walking speed of 5km per hr.

5km per hr + 30 min for every 300 metres of ascent

Note: The above speed is for someone who is reasonably fit, you will have to adjust your speed to the pace of the slowest person in your team or party.

ARGYLL OUTDOOR NAVIGATION