Maps (OCR GCSE Geography B)
Revision Note
Written by: Bridgette Barrett
Reviewed by: Jenna Quinn
Maps
Questions in the exam will be based on topographical maps
The maps can be from anywhere in the world
Maps will have a key, scale, northings and eastings
These all need to be used to answer the questions
Grid references
4-figure are used to locate specific grid squares within the map
The first two figures are the eastings which indicate how far east or west a grid is across the map
The second two figures are the northings which indicate how far north or south a grid is on the map
6-figure grid references are used to locate exact points within grid squares
The first three figures are the eastings
The second three figures are the northings
To find a 4 and 6 figure grid reference
First, find the four-figure grid reference by giving the number from the bottom of the map first and then the number from the side of the map.
4-Figure Grid Reference Step 1
4 - figure grid reference
In image above the 4-figure grid reference would be 17, 51
To give the 6-figure grid reference you need to image that the grid square is divided into 100 smaller squares
4-Figure Grid Reference Step 2
Examiner Tips and Tricks
The paper 2 exam will always contain a map. You will be expected to be able to give and use grid references to locate specific places on the map extract.
Scale
Maps in the exam will either be scale 1:25,000 where 1cm on the map = 25,000cm (250m) in real life or 1:50,000 where 1cm =50,000cm (500m) in real life
When the distance is straight or almost straight it can either be measured using a ruler or the edge of a straight piece of paper.
Using the scale at the bottom of the map mark distances are marked on a piece of paper.
This can then be laid from the first point to the second point to calculate the distance.
Measuring a Straight Line
A distance along a curved route can be divided, the paper rotated and marked in stages to calculate the full distance
To measure from A to B following the road on the map below the route can be divided into a series of straight sections using crosses.
The plain piece of paper can then be used to measure from A to the first cross. It should then be rotated, pivoting at the cross to mark the second cross.
Measuring a Curved Route
Bearings
Directions on a map should always be given using compass points
There are 16 compass points
16-Point Compass
A grid bearing is measured from grid north at 0o, East is 90o, South is 180o and West is 270o
Grid bearings are given using a protractor
The 0o should be pointing north and the centre of the protractor on the place the bearing is been given from
The compass direction and grid bearing from the crossroads at A to the location at B
Grid Bearing Diagram
On the map below B is South West of A
The bearing is 280°
Height
Height can be shown in three main ways;
Spot height
Contour lines
Trigonometrical stations
Spot heights show the height at a specific point with the height measurement written next to it
Contour lines are isolines. They join points of equal height and are usually at 5 or 10 meter intervals (distance between the contour line)
This means that the height of the land increases by 5 or 10 meters between the lines
Trigonometrical station is marked by a small black triangle with a height measurement written next to it
Topography
The contour lines can also indicate the shape and slope of the land or topography
Contour lines close together indicate steep land
Contour lines very far apart indicate gently sloping or flat land dependent on the distance apart
V-shaped valleys have a V-shaped set of contours
A hill is shown by a set of circular contour lines
Contour Lines Diagram
Contour lines
Cross-sections
A cross-section is a slice through the landscape
They are represented on a map by a line which is often labelled A at one end and B at the other
They use the contour lines to determine the height of the land
Map Cross-Section
A piece of paper is then laid along the line and points A and B are marked on
The contour lines are then marked each time they cross the paper
Contour Line Marking
These figures can then be used to create the cross-section
Cross-section Diagram
Examiner Tips and Tricks
In the exam you may be asked to finish a cross-section or interpret a cross-section. When interpreting cross-sections you should include;
The highest and lowest points
Comparison of slopes
Anamolies
Key
Maps can be used to identify a range of landscape features
These may be physical and human features
Each map has a key to show what the symbols mean
Typical Map Key
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