MAR-2-119R7 Map Information Part 2 First Class Training

Objectives Describe the main land features found on Ordnance Survey maps when planning routes Use contour lines on Ordnance Survey maps to plan routes Explain why land features shown on Ordnance Survey maps are important for planning routes Assess the slope gradient when planning routes Analyse sections of land profile by projection from map contour lines to get accurately from one point to the next Plan accurate routes using the features of an Ordnance Survey map 57. Objectives. Describe the main land features found on Ordnance Survey maps when planning routes Use contour lines on Ordnance Survey maps to plan routes Explain why land features shown on Ordnance Survey maps are important for planning routes Assess the slope gradient when planning routes Analyse sections of land profile by projection from map contour lines to get accurately from one point to the next Plan accurate routes using the features of an Ordnance Survey map

Relief Features such as hills and valleys Includes both height and shape Hard to represent on a two-dimensional map Shown by: Spot heights and trig points Contour lines 58. Introduction. The word “relief” means the rise and fall of the ground or, in other words such features as hills and valleys. This involves both the height and the shape of the land. As a map is drawn on a flat sheet of paper the representation of height and shape is difficult. Map makers have various ways of doing this, but whatever method, it is left to the reader to interpret the information. 59. Height. Methods of showing height on a map include: Spot heights and triangulation points, which are used to give an accurate height above sea level at given points. They give an indication of height but not shape. Contour lines, which are continuous lines linking points of equal height.

Height It is important to understand the units used OS maps are measured in metres 60. Unit of measurement. Units of height are important. In particular you must appreciate the difference between feet and metres, a foot being less than a third of a metre. OS maps are annotated in metres.

Shape Shape can be shown by: Hachures 61. Shape. Methods of showing shape include: Hachures. These are short tadpole-shaped strokes, the thicker end of the stroke being in the direction of the higher ground. When depicting steep ground they are drawn thickly and close together. On areas where the ground is a gentle slope, the hachures are drawn thinly and wider apart. This method gives no definite height indication and is seldom used except to show cuttings, embankments and steep slopes.

UPHILL Hachures. These are short tadpole-shaped strokes, the thicker end of the stroke being in the direction of the higher ground. When depicting steep ground they are drawn thickly and close together. On areas where the ground is a gentle slope, the hachures are drawn thinly and wider apart. This method gives no definite height indication and is seldom used except to show cuttings, embankments and steep slopes.

Shape Shape can be shown by: Hachures Thickness and closeness shows gradient Mostly used to show cuttings and embankments Hachures. These are short tadpole-shaped strokes, the thicker end of the stroke being in the direction of the higher ground. When depicting steep ground they are drawn thickly and close together. On areas where the ground is a gentle slope, the hachures are drawn thinly and wider apart. This method gives no definite height indication and is seldom used except to show cuttings, embankments and steep slopes.

Hachures. These are short tadpole-shaped strokes, the thicker end of the stroke being in the direction of the higher ground. When depicting steep ground they are drawn thickly and close together. On areas where the ground is a gentle slope, the hachures are drawn thinly and wider apart. This method gives no definite height indication and is seldom used except to show cuttings, embankments and steep slopes.

Hachures. These are short tadpole-shaped strokes, the thicker end of the stroke being in the direction of the higher ground. When depicting steep ground they are drawn thickly and close together. On areas where the ground is a gentle slope, the hachures are drawn thinly and wider apart. This method gives no definite height indication and is seldom used except to show cuttings, embankments and steep slopes.

Shape Shape can be shown by: Hachures Shading – not used on OS maps Contour lines Hill Shading. Hill shading is similar to hachures, but using an oblique stroke to achieve a depth of shading. This means that the darkest shading is the steepest ground. Another form of shading is based on a convention that light is shed from the NW corner and the hills are shaded accordingly. This method does not in itself give any indication of height. Contour lines. Contour lines on a map join all the points of the same height together and, with a little practice you can get from them a very good idea of the shape of the ground. So much so, they are the standard way in which height is depicted. There are some points to bear in mind before you start interpreting information from contour lines: Between any two contour lines there must be a slope either up or down. Contour lines are continuous and only stop abruptly at a cliff edge. Heights on contour lines are printed so that when you read them the right way up, you are facing uphill. The separation on contour lines is one line per five metres on a 1:25,000 scale map and one line per ten metres on a 1:50,000 scale map. Every fifty metres, the contour line is shown thicker than the surroundings (eg the fifty, one-hundred, one-hundred-and-fifty, etc lines are more prominent than the smaller intervals).

65 UPHILL 60 55 50 45 Contour lines. Contour lines on a map join all the points of the same height together and, with a little practice you can get from them a very good idea of the shape of the ground. So much so, they are the standard way in which height is depicted. There are some points to bear in mind before you start interpreting information from contour lines: Between any two contour lines there must be a slope either up or down. Contour lines are continuous and only stop abruptly at a cliff edge. Heights on contour lines are printed so that when you read them the right way up, you are facing uphill. The separation on contour lines is one line per five metres on a 1:25,000 scale map and one line per ten metres on a 1:50,000 scale map. Every fifty metres, the contour line is shown thicker than the surroundings (eg the fifty, one-hundred, one-hundred-and-fifty, etc lines are more prominent than the smaller intervals).

Shape Shape can be shown by: Hachures Shading – not used on OS maps Contour lines Link points of equal height Numbers always point up-hill Thicker line at 50m intervals Intervals 1:25,000 – 5m 1:50,000 – 10m Contour lines. Contour lines on a map join all the points of the same height together and, with a little practice you can get from them a very good idea of the shape of the ground. So much so, they are the standard way in which height is depicted. There are some points to bear in mind before you start interpreting information from contour lines: Between any two contour lines there must be a slope either up or down. Contour lines are continuous and only stop abruptly at a cliff edge. Heights on contour lines are printed so that when you read them the right way up, you are facing uphill. The separation on contour lines is one line per five metres on a 1:25,000 scale map and one line per ten metres on a 1:50,000 scale map. Every fifty metres, the contour line is shown thicker than the surroundings (eg the fifty, one-hundred, one-hundred-and-fifty, etc lines are more prominent than the smaller intervals).

68 Contour lines. Contour lines on a map join all the points of the same height together and, with a little practice you can get from them a very good idea of the shape of the ground. So much so, they are the standard way in which height is depicted. There are some points to bear in mind before you start interpreting information from contour lines: Between any two contour lines there must be a slope either up or down. Contour lines are continuous and only stop abruptly at a cliff edge. Heights on contour lines are printed so that when you read them the right way up, you are facing uphill. The separation on contour lines is one line per five metres on a 1:25,000 scale map and one line per ten metres on a 1:50,000 scale map. Every fifty metres, the contour line is shown thicker than the surroundings (eg the fifty, one-hundred, one-hundred-and-fifty, etc lines are more prominent than the smaller intervals).

50 68 65 60 55 Contour lines. Contour lines on a map join all the points of the same height together and, with a little practice you can get from them a very good idea of the shape of the ground. So much so, they are the standard way in which height is depicted. There are some points to bear in mind before you start interpreting information from contour lines: Between any two contour lines there must be a slope either up or down. Contour lines are continuous and only stop abruptly at a cliff edge. Heights on contour lines are printed so that when you read them the right way up, you are facing uphill. The separation on contour lines is one line per five metres on a 1:25,000 scale map and one line per ten metres on a 1:50,000 scale map. Every fifty metres, the contour line is shown thicker than the surroundings (eg the fifty, one-hundred, one-hundred-and-fifty, etc lines are more prominent than the smaller intervals). 50

Understanding Slopes The closer together contour lines are, the steeper the slope Remember to work out which way the slope goes! Use the numbers Slopes go uphill from small to larger numbers Numbers have their tops uphill from the bottoms Features give clues as well – eg lakes will generally form at the base of slopes rather than the top 62. Steepness and direction. If two contour lines are far apart it would suggest there is a greater distance to travel from one to the other to gain the height. This is better described as a gentle slope. If you see two contour lines very close together you would expect to see a very steep slope. The next few figures demonstrate these points well and with practice you too will be able to “see” when a climb will be hard (steep) or easy (gentle). It is not always easy to tell in the classroom whether a set of contours represents a steep upward or a steep downward slope. Remembering that contour values are always printed facing uphill this should give you a good guide in telling which way the slope is going. Other clues may be available to you, like rivers or lakes as these tend to be at the bottom of a slope.

Shallower slope 65 60 55 50 45 Steeper slope 65 60 55 50 45 62. Steepness and direction. If two contour lines are far apart it would suggest there is a greater distance to travel from one to the other to gain the height. This is better described as a gentle slope. If you see two contour lines very close together you would expect to see a very steep slope. The next few figures demonstrate these points well and with practice you too will be able to “see” when a climb will be hard (steep) or easy (gentle). It is not always easy to tell in the classroom whether a set of contours represents a steep upward or a steep downward slope. Remembering that contour values are always printed facing uphill this should give you a good guide in telling which way the slope is going. Other clues may be available to you, like rivers or lakes as these tend to be at the bottom of a slope.

Understanding Slopes A numerical figure can be calculated for how steep a slope is – the gradient Expressed as a ratio: The smaller the second number, the steeper the slope 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes 1:10 For every metre climbed (vertical distance), the slope covers 10 metres horizontal distance. 10 1 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes A numerical figure can be calculated for how steep a slope is – the gradient Expressed as a ratio: The smaller the second number, the steeper the slope To keep ratios understandable, the first number should always be a 1. This can be done by reducing the ratio (just like reducing a fraction). 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes 1:5 For every metre of vertical distance the slope covers 5 metres horizontal distance. 2:10 For every 2 metres of vertical distance the slope covers 10 metres horizontal distance. 1 2 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning. 10 5

Understanding Slopes Calculating the gradient: Count the gaps between the contour lines 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes 50 45 55 60 65 1 2 3 4 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes Calculating the gradient: Count the gaps between the contour lines Measure the horizontal distance 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes 65 60 4mm 55 50 45 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes Calculating the gradient: Count the gaps between the contour lines Measure the horizontal distance Convert both to metres (using the scale) 4 gaps x 5 metres = 20 m vertical 4mm x 25,000 4m x 25m = 100 m horizontal This gives 20:100 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

20 : 100 2 : 10 1 : 5 10 2 = 5 Understanding Slopes 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes If the gradient doesn’t easily reduce, then reduce the second figure to the nearest integer (whole number) 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

128 23 : 128 23 = 5 r15 1 : 6 Understanding Slopes Remainder is more than half of 23, so round up 1 : 6 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Or… Understanding Slopes 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

23 : 128 20 : 120 2 : 12 1 : 6 Understanding Slopes 23 ≈ 20 128 ≈ 120 23 ≈ 20 128 ≈ 120 20 : 120 2 : 12 1 : 6 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes If the gradient doesn’t easily reduce, then reduce the second figure to the nearest integer (whole number) In some cases, the second number is 1 and the first number is greater than one – this means that the slope is steeper than 45 degrees 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes 2:1 For every metre of horizontal distance, the slope rises 2 metres vertical distance. 1 2 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes If the gradient doesn’t easily reduce, then reduce the second figure to the nearest integer (whole number) In some cases, the second number is 1 and the first number is greater than one – this means that the slope is steeper than 45 degrees This can also be expressed as a ratio with a 1 followed by a fraction, eg the 2 : 1 slope can also be expressed as 1 : 0.5. 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes 1 : 0.5 For every metre of vertical distance, the slope rises half a metre of vertical distance. 0.5 1 63. Calculating gradient. Once the height difference is known (by knowing the height of two contour lines) and the distance between them measured (by use of the edge of a romer) the gradient can be calculated. The gradient is simply how far you have to travel along to go up or down a certain height – for instance a gradient of 1:20 (one-in-twenty) means that for every twenty metres you walk, you will have climbed (or descended) one metre. So if you measure 70m between two contour lines on a 1:25,000 scale map (5m intervals) the gradient would be 1:14(70÷5=14); a gentle slope. If after dividing the distance by the height you have a number smaller than one, the slope is steeper than 45° and probably worth avoiding! Choosing a route to avoid steep slopes (unless you really want to go climbing!) is a very important skill when planning.

Understanding Slopes Convex – steeper at the bottom than the top Concave slope Convex – steeper at the bottom than the top Concave – steeper at the top than at the bottom Some parts of a convex slope may not be visible from others The entirety of a concave slope can be seen from any part of the slope Convex slope 64. Convex/Concave. As well as being gradual or steep, slopes may be convex or concave. A slope is convex if the contours are closer together at the bottom; If the contours are further apart at the bottom then the slope is concave. It follows that if the contour lines are more evenly spaced, then the slope will be relatively uniform or straight. Knowing whether a slope is concave or convex is useful, as you will be unlikely to see the top of a convex slope from the bottom, or the bottom from the top. 65. Lie of the land. Where contours meander and are varying distances apart, but never very close, the ground is undulating and relatively flat. You can only gain a little knowledge of the ground from the sparse detail, but the land will fall gentle from the higher contour to the lower one.

80 Convex slope 75 70 65 60 55 64. Convex/Concave. As well as being gradual or steep, slopes may be convex or concave. A slope is convex if the contours are closer together at the bottom; If the contours are further apart at the bottom then the slope is concave. It follows that if the contour lines are more evenly spaced, then the slope will be relatively uniform or straight. Knowing whether a slope is concave or convex is useful, as you will be unlikely to see the top of a convex slope from the bottom, or the bottom from the top. 65. Lie of the land. Where contours meander and are varying distances apart, but never very close, the ground is undulating and relatively flat. You can only gain a little knowledge of the ground from the sparse detail, but the land will fall gentle from the higher contour to the lower one. 50 45

80 75 Concave slope 70 65 60 55 50 64. Convex/Concave. As well as being gradual or steep, slopes may be convex or concave. A slope is convex if the contours are closer together at the bottom; If the contours are further apart at the bottom then the slope is concave. It follows that if the contour lines are more evenly spaced, then the slope will be relatively uniform or straight. Knowing whether a slope is concave or convex is useful, as you will be unlikely to see the top of a convex slope from the bottom, or the bottom from the top. 45

Undulation Only features larger than the contour interval will show on contours – but the land between contours could undulate significantly This is the reason why hachures are used for notable features too small to show with contours 10 15 15 15 10 65. Lie of the land. Where contours meander and are varying distances apart, but never very close, the ground is undulating and relatively flat. You can only gain a little knowledge of the ground from the sparse detail, but the land will fall gentle from the higher contour to the lower one.

Land Features - Ridge A long narrow stretch of elevated ground 66. Ridges, saddles and cols. A ridge is a long narrow stretch of elevated ground; it is also known as a saddle. Where a ridge has a peak at each end, the lower part of the ridge between the summits is called a col.

823 66. Ridges, saddles and cols. A ridge is a long narrow stretch of elevated ground; it is also known as a saddle. Where a ridge has a peak at each end, the lower part of the ridge between the summits is called a col.

780 785 790 795 800 805 810 RIDGE 815 820 820 815 810 805 800 795 823 790 785 780 775 770 765 66. Ridges, saddles and cols. A ridge is a long narrow stretch of elevated ground; it is also known as a saddle. Where a ridge has a peak at each end, the lower part of the ridge between the summits is called a col.

Land Features - Ridge A long narrow stretch of elevated ground If between two peaks, it is known as a col or a saddle 66. Ridges, saddles and cols. A ridge is a long narrow stretch of elevated ground; it is also known as a saddle. Where a ridge has a peak at each end, the lower part of the ridge between the summits is called a col.

847 66. Ridges, saddles and cols. A ridge is a long narrow stretch of elevated ground; it is also known as a saddle. Where a ridge has a peak at each end, the lower part of the ridge between the summits is called a col.

COL (SADDLE) 847 66. Ridges, saddles and cols. A ridge is a long narrow stretch of elevated ground; it is also known as a saddle. Where a ridge has a peak at each end, the lower part of the ridge between the summits is called a col.

Land Features - Valley A valley is the inverse of a ridge 67. Valley. The opposite of a ridge (a long depression).

67. Valley. The opposite of a ridge (a long depression).

v VALLEY 67. Valley. The opposite of a ridge (a long depression).

Land Features – Spur A spur can be thought of as a ridge running perpendicular to a slope. It is a bit like half a col: SPUR COL 68. Spurs And re-entrants. A spur is a piece of high ground jutting from a range of hills into lower ground. A re-entrant is a narrow valley closed at one end, separating two spurs. They are very similar on the map because the contours for both will have a hairpin shape. You will need to study the contour heights and decide whether the closed part of the hairpin points to the high or low ground. If the closed part points in the direction of the lower ground it is a spur - shown in the diagram. If the closed part points towards the higher ground it is a re-entrant. The fact that spurs stick out can be remembered by the fact that a riding boot has spurs which stick out – re-entrant contains the word 'enter' (or 'entrance') which means to go in.

847 68. Spurs And re-entrants. A spur is a piece of high ground jutting from a range of hills into lower ground. A re-entrant is a narrow valley closed at one end, separating two spurs. They are very similar on the map because the contours for both will have a hairpin shape. You will need to study the contour heights and decide whether the closed part of the hairpin points to the high or low ground. If the closed part points in the direction of the lower ground it is a spur - shown in the diagram. If the closed part points towards the higher ground it is a re-entrant. The fact that spurs stick out can be remembered by the fact that a riding boot has spurs which stick out – re-entrant contains the word 'enter' (or 'entrance') which means to go in.

SPUR 847 68. Spurs And re-entrants. A spur is a piece of high ground jutting from a range of hills into lower ground. A re-entrant is a narrow valley closed at one end, separating two spurs. They are very similar on the map because the contours for both will have a hairpin shape. You will need to study the contour heights and decide whether the closed part of the hairpin points to the high or low ground. If the closed part points in the direction of the lower ground it is a spur - shown in the diagram. If the closed part points towards the higher ground it is a re-entrant. The fact that spurs stick out can be remembered by the fact that a riding boot has spurs which stick out – re-entrant contains the word 'enter' (or 'entrance') which means to go in.

Land Features – Re-entrant A re-entrant is essentially the opposite of a spur Re-entrants are common on mountains, streams often cut channels out by erosion To remember which is which: Spurs – pointy Re-entrant – ‘enters’ the slope Re-entrants and spurs often occur next to each other The difference between a valley and a re-entrant is the gradient of the bottom Re-entrants are on slopes, so have a steep gradient Valleys have shallow bottoms 68. Spurs And re-entrants. A spur is a piece of high ground jutting from a range of hills into lower ground. A re-entrant is a narrow valley closed at one end, separating two spurs. They are very similar on the map because the contours for both will have a hairpin shape. You will need to study the contour heights and decide whether the closed part of the hairpin points to the high or low ground. If the closed part points in the direction of the lower ground it is a spur - shown in the diagram. If the closed part points towards the higher ground it is a re-entrant. The fact that spurs stick out can be remembered by the fact that a riding boot has spurs which stick out – re-entrant contains the word 'enter' (or 'entrance') which means to go in.

134 131 68. Spurs And re-entrants. A spur is a piece of high ground jutting from a range of hills into lower ground. A re-entrant is a narrow valley closed at one end, separating two spurs. They are very similar on the map because the contours for both will have a hairpin shape. You will need to study the contour heights and decide whether the closed part of the hairpin points to the high or low ground. If the closed part points in the direction of the lower ground it is a spur - shown in the diagram. If the closed part points towards the higher ground it is a re-entrant. The fact that spurs stick out can be remembered by the fact that a riding boot has spurs which stick out – re-entrant contains the word 'enter' (or 'entrance') which means to go in.

RE-ENTRANT 134 131 68. Spurs And re-entrants. A spur is a piece of high ground jutting from a range of hills into lower ground. A re-entrant is a narrow valley closed at one end, separating two spurs. They are very similar on the map because the contours for both will have a hairpin shape. You will need to study the contour heights and decide whether the closed part of the hairpin points to the high or low ground. If the closed part points in the direction of the lower ground it is a spur - shown in the diagram. If the closed part points towards the higher ground it is a re-entrant. The fact that spurs stick out can be remembered by the fact that a riding boot has spurs which stick out – re-entrant contains the word 'enter' (or 'entrance') which means to go in.

Land Features - Escarpment A continuous cliff, running for many kilometres 69. Escarpment. An escarpment is a ridge with a steep slope (often a cliff) on one side and a shallower slop on the other.

69. Escarpment. An escarpment is a ridge with a steep slope (often a cliff) on one side and a shallower slop on the other.

ESCARPMENT 69. Escarpment. An escarpment is a ridge with a steep slope (often a cliff) on one side and a shallower slop on the other.

Land Features - Knoll A knoll is an isolated hill 70. Knoll. An isolated hill.

68 70. Knoll. An isolated hill.

50 KNOLL 68 65 60 55 70. Knoll. An isolated hill. 50

Summary Contour lines: Contour lines link points of the same height. The numbers point up-hill The closer contours are together, the steeper the slope. You can't normally see all of a convex slope at once when you're next to/on it – a convex slope is one that gets steeper at the bottom and shallower at the top. Gradient is height-gained : distance-travelled 71. End of lesson drill. Summary of key points. Contour lines: Contour lines link points of the same height. The numbers point up-hill The closer contours are together, the steeper the slope. You can't normally see all of a convex slope at once when you're next to/on it – a convex slope is one that gets steeper at the bottom and shallower at the top. Gradient is height-gained : distance-travelled Features: A ridge is a long, raised feature If a ridge has a hill/mountain at both ends, the middle is called a col A valley is a long, lowered feature Spurs stick out, re-entrants stick in (think spurs on boots and entrances). Escarpments are steep on one side, shallow on the other.

Summary Features: A ridge is a long, raised feature If a ridge has a hill/mountain at both ends, the middle is called a col A valley is a long, lowered feature Spurs stick out, re-entrants stick in (think spurs on boots and entrances). Escarpments are steep on one side, shallow on the other. 71. End of lesson drill. Summary of key points. Contour lines: Contour lines link points of the same height. The numbers point up-hill The closer contours are together, the steeper the slope. You can't normally see all of a convex slope at once when you're next to/on it – a convex slope is one that gets steeper at the bottom and shallower at the top. Gradient is height-gained : distance-travelled Features: A ridge is a long, raised feature If a ridge has a hill/mountain at both ends, the middle is called a col A valley is a long, lowered feature Spurs stick out, re-entrants stick in (think spurs on boots and entrances). Escarpments are steep on one side, shallow on the other.

Objectives Describe the main land features found on Ordnance Survey maps when planning routes Use contour lines on Ordnance Survey maps to plan routes Explain why land features shown on Ordnance Survey maps are important for planning routes Assess the slope gradient when planning routes Analyse sections of land profile by projection from map contour lines to get accurately from one point to the next Plan accurate routes using the features of an Ordnance Survey map 57. Objectives. Describe the main land features found on Ordnance Survey maps when planning routes Use contour lines on Ordnance Survey maps to plan routes Explain why land features shown on Ordnance Survey maps are important for planning routes Assess the slope gradient when planning routes Analyse sections of land profile by projection from map contour lines to get accurately from one point to the next Plan accurate routes using the features of an Ordnance Survey map

Any Questions? Questions to and from the class. Look forward to next lesson.