Recruit Training Flight Lesson 5 Part 3 Map Reading
Shape of the Land • On the OS Maps we have contour lines which show us the SHAPE of the land. • This is important to know, as when looking for the best route, the shortest route might not always be the quickest. • For example, sometimes it may take less time to walk round a hill than to go over the hill depending on the height. • The contour lines will show us the RELIEF or shape of the land so we can decide the best route.
Contours • Contours on the map are a way of representing height of the ground on your flat piece of paper. • On a 1:5000 OS map, the contours are every 10m • On a 1:2500 OS map, the contours are every 5m • Occasionally, the contours are marked with their heights to best aid working out the land shape. • We can tell the shape of the land by looking at the shapes of the contours and by looking at the direction the slopes.
At Point A walking to Point B – I am travelling DOWNHILL because the contour numbers are upside down if I orientate the map, ie I am looking DOWN the slope! At Point A walking to Point C – I am travelling UPHILL because the contour numbers are the correct way up if I orientate the map, ie I am looking UP the slope! A B C
Shape of the Land • Contours show us the shape of the land.
Slopes • Where contours are close together, the slope is Steep • Where they are further apart, the slope is gradual
Task • Draw what you think the slope of this hill will be like: 20 10 30 40 50
Spot Heights & Trig Points • On maps you sometimes get a height marked on which is not on a contour line. • This is a Spot Height. • A Trig Point is also a height at a particular point, but a Trip Point will have a physical marker on the ground and is marked in a Blue Triangle. Spot Height Trig Point
Although this route may look straight forward, have a look at the video of the route on the squadron website. • LINK
Contour Summary • Contour lines join areas of the same height. • The closer together a set of contour lines, the steeper the slope. • The further apart the contour lines, the shallower the slope. • On a 1:25,000 scale map, contour lines = 5m • On a 1:50,000 scale map, contour lines = 10m
Questions for You • A “Roamer” would be used in finding: • a. The direction of a track • b. The grid reference point • c. The average gradient • d. A relative bearing
Questions for You • What is the meaning of the two letters in a Grid Reference using the UK National Grid e.g. a Grid Reference of TL307624? • a. The point is located in one of the Grid squares with sides of 500Km • b. The point is located in one of the Grid squares with sides of 1Km • c. The point is located in one of the Grid squares with sides of 100Km • d. The point is located 30Km East and 62Km North of origins of the grid
Questions for You • In map reading, what does the word “relief” mean? • a. Hill shading • b. Layer tinting • c. The rise and fall of the land • d. Hachuring
Questions for You • What shape would the contours be for a spur? • a. Round • b. Elliptical • c. Hairpin • d. Straight
Questions for You • If you were to rotate the map so that the figures on the contour lines were the right way up, which way would you be looking? • a. Down the slope depicted by the contours • b. Up the slope depicted by the contours • c. Grid North • d. True North
Questions for You • What must there be between any two adjacent contour lines (on a map) which have different values? • a. Flat land • b. A slope • c. A ridge • d. A spur
Questions for You • If, by studying a map, you cannot be sure whether one place can be seen from another, what can you do to decide? • a. Draw a cross-section of the land between them • b. Calculate the gradient between them • c. Calculate the mean contour line • d. Calculate the height of the land by reference to the spot heights in the area
By The End of the Lesson • You will be able to find a point indicated by a 6 figure grid reference; • You will be able to give a 6 figure grid reference for a point on a standard OS map; • You will be able to look at gradients on a map and be able to visualise the land form; • You will have a good knowledge of OS style maps, map scales, symbols and features.
Look Ahead • Your next lesson will be on Initial Expedition Training