G
Guest
Guest
To be used in conjunction with Ordnance Survey Map Sheet 119 Buxton & Matlock
Map reading lesson 1
Introduction, Use, Care, reliability, and marginal information.
What is a map?
A map is a bird’s eye view of the ground, drawn to scale on a piece of paper.
Use of maps. Interpretation of information.
Map reading is not an end to itself. A map is just a means of communicating information between users. It is the responsibility of the user to select and interpret the information required for the purpose in hand.
Care
Whilst maps are relatively inexpensive abuse is never warranted, wherever possible avoid marking maps, as marks obscure other information, and in extreme cases can lead to false interpretation of information. Rain ruins maps, as does repeated folding making new creases.
Reliability
A map is only reliable when it is being drawn. On the date it is published, it is already out of date. For example: woods come and go as do buildings. New roads are constantly being laid and houses built in areas previously considered inaccessible. Foreign maps can be out of date by up to twenty years when first published and showing first edition. Maps are frequently reprinted without revision. Therefore, a new map may not actually be that, and as a result, care should be exercised when interpreting any information contained.
Marginal Information
Contains all the details needed for interpretation of the map. Because maps are generally folded and the margins normally out of sight, users should familiarise them selves with all information. Especially the conventional signs used to interpret the topographical information. It is always worth spending time checking this information as from time to time conventional signs do change. Other information contained include map title and sheet numbers, details of scale, publishing dates, the grid magnetic angle and annual change, and a reminder of the grid reference system.
For this basic introduction, I would like you all to study the marginal information, mainly the conventional signs, and familiarise yourselves with the differences between similar signs ie; Footpaths, Bridleways and roads used as a public paths.
Map Reading 2
The Grid Reference system
The grid reference system can be used on all ordnance survey maps of Great Britain at all scales. Britain is divided into 100km grid squares, each square being identified by two letters. These letters can be found in the corners of each map in hollow blue letters. Generally, these should always be quoted before the figures in a GR sequence.
Each map is divided into 1km squares by fine blue lines. The lines running vertically and progressively numbered from left to right (in an easterly direction) are known as Easting’s and are the first set of figures quoted in a GR. The lines running horizontally and progressively numbered from bottom to top (in a northerly direction) are known as Northing’s, and are the second set of numbers quoted in a GR. To remember this sequence, say, “Along the corridor and up the stairs”
Four figure GRs
To find a four figure GR (correct to 1km on the ground). First - along the corridor, read the two numbers found on the bottom of the map. Second - up the stairs, read the two numbers on the side of the map. Follow the line up and across, where the lines meet you have the bottom left hand corner of a 1km grid square. Four figure Grs are useful to give a general area or an obvious feature.
Using the conventional signs in marginal information answer the following questions:
1. Describe the difference between the woods in grid square SK 2576 and SK 2869
2. What is the farm called in grid square SK 2077
3. What is the village called in grid square SK 1575
4. What is the main feature of grid square SK 2074
5. What is the main right of way shown running through grid square SK 1572
Six figure GRs
These are the Grs normally used in map reading and are accurate to 100m on the ground. A deviation of no more than one digit incorrect is the minimum acceptable standard.
To find a six figure GR first separate the six figures into two groups of three. Using the first, two figures in the first group, and the first two figures in the second group, find the four figure GR you now have. Having found the square using the third figure of each group, estimate the approx number of tenths - along the corridor and up the stairs. Where the imaginary lines intersect, you now have a six figure GR.
Find Intake farm at GR SK 164794. So……SK….16 & 4 tenths...94 & 4 tenths.
What are at the following Grid references? SK omitted in all cases.
a. 215779
b. 216777
c. 199779
d. 181748
e. 152758
f. 154742
g. 155774
h. 232743
i. 262747
j. 261885
k. 201692
l. 158764
m. 137752
n. 138745
o. 183747
Now, find and post the six figure grid references of the following conventional signs: Do not use the ones above!
1. Public house
2. Telephone
3. Post office
4. Viewpoint
5. Camping or caravan site
6. Picnic area
7. Parking area
8. Toilets
9. Radio or TV mast
10. Church
Please PM or e - mail answers to me.
Map Reading lesson 3
Scales and measuring distance
All maps as we know are drawn to scale. The most popular scales we use are 1:50 000 and 1:25 000. This just means that, for example 1:50 000, each item in reality is 50 000 times smaller on paper. Alternatively, 1cm on the map is 50 000 cm on the ground (500 metres). Making it easier still each grid square is 2cm square; therefore, each grid square is 1 kilometre square. On a 1:25 000 map each grid square is still 1km square but measures 4cm, so there is more detail shown. There are many other scales used on maps, possibly the other one you will come across is 1:63 360, 1” to 1 mile, if you remember old money. These are quite commonly used on motoring or tourist maps.
This makes it easy for us to estimate distances between points in a straight line. As by now, you should be familiar with six figure grid references and subdividing each square into tenths, so you can into equal tenths that equal 100 meters.
From GR SK 181756 to GR SK 253723 is approximately 9.8km, 10ks would be near enough if driving.
To be more accurate, you need to use other methods. There are various small-wheeled devices available to draw over the route and then reverse the procedure on the drawn scale at the bottom centre of the map. This gives a more accurate distance. Other methods include, non-stretchy string, held at the start point and moved around the chosen route, following each twist and turn. Again measured on the scale at the bottom. Paper method, Taking a straight edge of paper mark a line for the start, move the paper round the route following each twist and turn, similar to string, again re measure on the scale at the bottom of the map. Probably the most accurate method.
Using one of the above methods, measure the distance from:
GR SK 210777 to GR SK 224780 via the ORPA
GR SK 236736 to GR SK 268789 via road
GR SK 176780 to GR SK 204788 via the quickest route.
Please PM or e - mail answers to me.
Map Reading lesson 4
Introduction to the compass
During this course of instruction we will not be using a magnetic compass. However, you still need to know the four cardinal compass points of North, East, South, and West. You also need to know the four intermediate points of Northeast, Southeast, Southwest and Northwest. If you imagine a clock face,
North is 12, East is 3, South is 6, West is 9.
Northeast is between 1 and 2. Southeast is between 4 and 5. Southwest is between 7 and 8. Northwest is between 10 and 11.
In addition, on a map we have three North points:
True North, which as it states points true North.
Magnetic North, which is influenced by the earths magnetic field and varies a few degrees(or mils if you prefer) each year. More information of how this varies is found in marginal information at the top centre of the map. This is called the Grid magnetic angle, and the annual change is given. The grid magnetic angle is measured between magnetic North and Grid North.
Grid North is simply the direction of the vertical grid lines (which we now know as eastings). North is always the top of the map. If grid lines were to magnetic or true north, they would not form squares, but be wider at the bottom and narrow at the top(at least they would in the northern hemisphere).
For your home work this time, Simply work out the grid magnetic angle now, from when the map was published, Read carefully the GMA. This is just to give you some advance on should we use magnetic compasses in the future, and need to convert bearings from magnetic to grid or vice versa.
Also, try and fit in these points:
North north east, East north east, East south east, South south east, South south west, West south west, West north west and North north west
Map Reading lesson 5
Setting a map to ground, compass and landmarks
When using a map on the ground, it is usually easier to orientate the map to the ground. Ladies tend to do this instinctively, whilst men tend to look at the map with grid north to the top. Reading the map on the ground with grid north to the top requires practice, is usually harder and can lead to some basic mistakes, especially when tired or rushed into a decision.
The easiest way to align a map is with a compass. The compass needle points to magnetic north, line magnetic north on the map with the compass needle. Your map is now set to ground and normally easier to follow.
If you already know the direction of true north, you can use this method and turn the map. Just be 100% sure you are correct.
Alternate methods of finding north will be dealt with later.
The most common method of setting map to ground is by landmarks and eye. Pick out two or three prominent objects, road junctions, churches, woods or similar. Turn the map so that the chosen objects you can see are in the correct place in relation to the map.
This is not something you can readily practice until out on the ground, but once mastered makes position and route finding easier.
Map reading lesson 6
Relief, Vertical Interval and Interpretation of Contours
To understand the shape of the ground from a map is a skill. Once learnt it needs practice. Understand the basics and the rest will follow. A contour line is a pale brown line joining points of equal heights above sea level. The interval between contour lines (vertical interval) is normally 10m, but can vary with the scale of map. Older maps, non-metric, show contours at 50 feet (16m) so check in marginal information.
If contour lines are close together then the ground is steep. In some very steep areas, contour lines can merge or blend. Take a look around Grid 178794.
One way of visualising contour lines as landscape is to think of the sea at high tide leaving a mark, and another every 10m on its way out.
Land with little or no contours, is generally flat When trying to visualise the land, remember contours are numbered upwards in height. Two flat areas, Grid 2676 and grid 2973.
Try to imagine, stood at the bottom contour looking up. If the lines are tighter at the bottom and more spaced towards the top you have a convex slope, Grid 165727 to grid 162724. If spaced at bottom, tight at top, concave, Grid 248751 to grid 256754. Even all way, even slope. Of course, you have all the variants in between.
Other things to look for are rivers; these always run downhill and tend to run into or along valleys, Grid 177721.
A valley is a V shaped hill, two ways to interpret a valley, rivers and the V. The V should be pointing upwards in height, Grid 177721.
You should also look for the conventional signs for Cliffs, Rocks, Scree and Outcrops to give a guide, Grid 174753.
It is always worth bearing in mind that fluctuations of 9m or less do not show on maps with a vertical interval of 10m. When planning walks, this can give a few surprises, like false summits. When planning drives, this can also mean little surprises although embankments and such will be shown.
Now using the skills you have acquired; examine carefully an area of the map of your choice. E mail or PM me a detailed description like the example I’ve given below. Use Grid references, conventional signs, distance and a description of the ground. DO NOT pick an airfield and say it’s flat, whilst this maybe true, it does not demonstrate whether you have gained any knowledge.
Route Card. Sheet 119 Buxton & Matlock. Approx 3 miles (4.8Km)
1. Start PH at 243778 in Grindleford. Follow the minor road sharply uphill to the North West. After approx 2 Kim’s (1¼ miles) the road bears sharply left (South).
2. Follow the ORPA, road directly ahead of you at this point, Grid 224780. Climbing over the hill with a radio/tv mast to your left and a triangulation (trig) point to your right.
3. After passing the mast you will cross a small knoll before descending to a minor road at Grid 209778.
4. Ahead in approx 100m is another ORPA to the right (North West) on your right. Take this passing a small coniferous wood on your right before rejoining a minor road that bends left (South West) to another pub at Grid 200779.
The largest map I can reproduce here giving an idea of the area:
Having completed this short course of instruction, should now give you the basic knowledge to practice with and improve upon. Only by constant practice and relating the map to ground in all weathers can you hope to be a fully competent map reader.
Good luck and remember to ask as many questions as needed.
Copyright2007 www.calm-photography.co.uk Cameraman Andy Birks
Map reading lesson 1
Introduction, Use, Care, reliability, and marginal information.
What is a map?
A map is a bird’s eye view of the ground, drawn to scale on a piece of paper.
Use of maps. Interpretation of information.
Map reading is not an end to itself. A map is just a means of communicating information between users. It is the responsibility of the user to select and interpret the information required for the purpose in hand.
Care
Whilst maps are relatively inexpensive abuse is never warranted, wherever possible avoid marking maps, as marks obscure other information, and in extreme cases can lead to false interpretation of information. Rain ruins maps, as does repeated folding making new creases.
Reliability
A map is only reliable when it is being drawn. On the date it is published, it is already out of date. For example: woods come and go as do buildings. New roads are constantly being laid and houses built in areas previously considered inaccessible. Foreign maps can be out of date by up to twenty years when first published and showing first edition. Maps are frequently reprinted without revision. Therefore, a new map may not actually be that, and as a result, care should be exercised when interpreting any information contained.
Marginal Information
Contains all the details needed for interpretation of the map. Because maps are generally folded and the margins normally out of sight, users should familiarise them selves with all information. Especially the conventional signs used to interpret the topographical information. It is always worth spending time checking this information as from time to time conventional signs do change. Other information contained include map title and sheet numbers, details of scale, publishing dates, the grid magnetic angle and annual change, and a reminder of the grid reference system.
For this basic introduction, I would like you all to study the marginal information, mainly the conventional signs, and familiarise yourselves with the differences between similar signs ie; Footpaths, Bridleways and roads used as a public paths.
Map Reading 2
The Grid Reference system
The grid reference system can be used on all ordnance survey maps of Great Britain at all scales. Britain is divided into 100km grid squares, each square being identified by two letters. These letters can be found in the corners of each map in hollow blue letters. Generally, these should always be quoted before the figures in a GR sequence.
Each map is divided into 1km squares by fine blue lines. The lines running vertically and progressively numbered from left to right (in an easterly direction) are known as Easting’s and are the first set of figures quoted in a GR. The lines running horizontally and progressively numbered from bottom to top (in a northerly direction) are known as Northing’s, and are the second set of numbers quoted in a GR. To remember this sequence, say, “Along the corridor and up the stairs”
Four figure GRs
To find a four figure GR (correct to 1km on the ground). First - along the corridor, read the two numbers found on the bottom of the map. Second - up the stairs, read the two numbers on the side of the map. Follow the line up and across, where the lines meet you have the bottom left hand corner of a 1km grid square. Four figure Grs are useful to give a general area or an obvious feature.
Using the conventional signs in marginal information answer the following questions:
1. Describe the difference between the woods in grid square SK 2576 and SK 2869
2. What is the farm called in grid square SK 2077
3. What is the village called in grid square SK 1575
4. What is the main feature of grid square SK 2074
5. What is the main right of way shown running through grid square SK 1572
Six figure GRs
These are the Grs normally used in map reading and are accurate to 100m on the ground. A deviation of no more than one digit incorrect is the minimum acceptable standard.
To find a six figure GR first separate the six figures into two groups of three. Using the first, two figures in the first group, and the first two figures in the second group, find the four figure GR you now have. Having found the square using the third figure of each group, estimate the approx number of tenths - along the corridor and up the stairs. Where the imaginary lines intersect, you now have a six figure GR.
Find Intake farm at GR SK 164794. So……SK….16 & 4 tenths...94 & 4 tenths.
What are at the following Grid references? SK omitted in all cases.
a. 215779
b. 216777
c. 199779
d. 181748
e. 152758
f. 154742
g. 155774
h. 232743
i. 262747
j. 261885
k. 201692
l. 158764
m. 137752
n. 138745
o. 183747
Now, find and post the six figure grid references of the following conventional signs: Do not use the ones above!
1. Public house
2. Telephone
3. Post office
4. Viewpoint
5. Camping or caravan site
6. Picnic area
7. Parking area
8. Toilets
9. Radio or TV mast
10. Church
Please PM or e - mail answers to me.
Map Reading lesson 3
Scales and measuring distance
All maps as we know are drawn to scale. The most popular scales we use are 1:50 000 and 1:25 000. This just means that, for example 1:50 000, each item in reality is 50 000 times smaller on paper. Alternatively, 1cm on the map is 50 000 cm on the ground (500 metres). Making it easier still each grid square is 2cm square; therefore, each grid square is 1 kilometre square. On a 1:25 000 map each grid square is still 1km square but measures 4cm, so there is more detail shown. There are many other scales used on maps, possibly the other one you will come across is 1:63 360, 1” to 1 mile, if you remember old money. These are quite commonly used on motoring or tourist maps.
This makes it easy for us to estimate distances between points in a straight line. As by now, you should be familiar with six figure grid references and subdividing each square into tenths, so you can into equal tenths that equal 100 meters.
From GR SK 181756 to GR SK 253723 is approximately 9.8km, 10ks would be near enough if driving.
To be more accurate, you need to use other methods. There are various small-wheeled devices available to draw over the route and then reverse the procedure on the drawn scale at the bottom centre of the map. This gives a more accurate distance. Other methods include, non-stretchy string, held at the start point and moved around the chosen route, following each twist and turn. Again measured on the scale at the bottom. Paper method, Taking a straight edge of paper mark a line for the start, move the paper round the route following each twist and turn, similar to string, again re measure on the scale at the bottom of the map. Probably the most accurate method.
Using one of the above methods, measure the distance from:
GR SK 210777 to GR SK 224780 via the ORPA
GR SK 236736 to GR SK 268789 via road
GR SK 176780 to GR SK 204788 via the quickest route.
Please PM or e - mail answers to me.
Map Reading lesson 4
Introduction to the compass
During this course of instruction we will not be using a magnetic compass. However, you still need to know the four cardinal compass points of North, East, South, and West. You also need to know the four intermediate points of Northeast, Southeast, Southwest and Northwest. If you imagine a clock face,
North is 12, East is 3, South is 6, West is 9.
Northeast is between 1 and 2. Southeast is between 4 and 5. Southwest is between 7 and 8. Northwest is between 10 and 11.
In addition, on a map we have three North points:
True North, which as it states points true North.
Magnetic North, which is influenced by the earths magnetic field and varies a few degrees(or mils if you prefer) each year. More information of how this varies is found in marginal information at the top centre of the map. This is called the Grid magnetic angle, and the annual change is given. The grid magnetic angle is measured between magnetic North and Grid North.
Grid North is simply the direction of the vertical grid lines (which we now know as eastings). North is always the top of the map. If grid lines were to magnetic or true north, they would not form squares, but be wider at the bottom and narrow at the top(at least they would in the northern hemisphere).
For your home work this time, Simply work out the grid magnetic angle now, from when the map was published, Read carefully the GMA. This is just to give you some advance on should we use magnetic compasses in the future, and need to convert bearings from magnetic to grid or vice versa.
Also, try and fit in these points:
North north east, East north east, East south east, South south east, South south west, West south west, West north west and North north west
Map Reading lesson 5
Setting a map to ground, compass and landmarks
When using a map on the ground, it is usually easier to orientate the map to the ground. Ladies tend to do this instinctively, whilst men tend to look at the map with grid north to the top. Reading the map on the ground with grid north to the top requires practice, is usually harder and can lead to some basic mistakes, especially when tired or rushed into a decision.
The easiest way to align a map is with a compass. The compass needle points to magnetic north, line magnetic north on the map with the compass needle. Your map is now set to ground and normally easier to follow.
If you already know the direction of true north, you can use this method and turn the map. Just be 100% sure you are correct.
Alternate methods of finding north will be dealt with later.
The most common method of setting map to ground is by landmarks and eye. Pick out two or three prominent objects, road junctions, churches, woods or similar. Turn the map so that the chosen objects you can see are in the correct place in relation to the map.
This is not something you can readily practice until out on the ground, but once mastered makes position and route finding easier.
Map reading lesson 6
Relief, Vertical Interval and Interpretation of Contours
To understand the shape of the ground from a map is a skill. Once learnt it needs practice. Understand the basics and the rest will follow. A contour line is a pale brown line joining points of equal heights above sea level. The interval between contour lines (vertical interval) is normally 10m, but can vary with the scale of map. Older maps, non-metric, show contours at 50 feet (16m) so check in marginal information.
If contour lines are close together then the ground is steep. In some very steep areas, contour lines can merge or blend. Take a look around Grid 178794.
One way of visualising contour lines as landscape is to think of the sea at high tide leaving a mark, and another every 10m on its way out.
Land with little or no contours, is generally flat When trying to visualise the land, remember contours are numbered upwards in height. Two flat areas, Grid 2676 and grid 2973.
Try to imagine, stood at the bottom contour looking up. If the lines are tighter at the bottom and more spaced towards the top you have a convex slope, Grid 165727 to grid 162724. If spaced at bottom, tight at top, concave, Grid 248751 to grid 256754. Even all way, even slope. Of course, you have all the variants in between.
Other things to look for are rivers; these always run downhill and tend to run into or along valleys, Grid 177721.
A valley is a V shaped hill, two ways to interpret a valley, rivers and the V. The V should be pointing upwards in height, Grid 177721.
You should also look for the conventional signs for Cliffs, Rocks, Scree and Outcrops to give a guide, Grid 174753.
It is always worth bearing in mind that fluctuations of 9m or less do not show on maps with a vertical interval of 10m. When planning walks, this can give a few surprises, like false summits. When planning drives, this can also mean little surprises although embankments and such will be shown.
Now using the skills you have acquired; examine carefully an area of the map of your choice. E mail or PM me a detailed description like the example I’ve given below. Use Grid references, conventional signs, distance and a description of the ground. DO NOT pick an airfield and say it’s flat, whilst this maybe true, it does not demonstrate whether you have gained any knowledge.
Route Card. Sheet 119 Buxton & Matlock. Approx 3 miles (4.8Km)
1. Start PH at 243778 in Grindleford. Follow the minor road sharply uphill to the North West. After approx 2 Kim’s (1¼ miles) the road bears sharply left (South).
2. Follow the ORPA, road directly ahead of you at this point, Grid 224780. Climbing over the hill with a radio/tv mast to your left and a triangulation (trig) point to your right.
3. After passing the mast you will cross a small knoll before descending to a minor road at Grid 209778.
4. Ahead in approx 100m is another ORPA to the right (North West) on your right. Take this passing a small coniferous wood on your right before rejoining a minor road that bends left (South West) to another pub at Grid 200779.
The largest map I can reproduce here giving an idea of the area:
Having completed this short course of instruction, should now give you the basic knowledge to practice with and improve upon. Only by constant practice and relating the map to ground in all weathers can you hope to be a fully competent map reader.
Good luck and remember to ask as many questions as needed.
Copyright2007 www.calm-photography.co.uk Cameraman Andy Birks
