Cartographic skills (Cambridge International IGCSE Geography)

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

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

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

  • To find the four-figure grid reference, give the number from the bottom of the map first, then the number from the side

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 imagine that the grid square is divided into 100 smaller squares

Six figure grid reference

Worked Example Figure 1.1 shows some of the features around the main settlement at Misterbianco in the north-east of the map extract

What is the six-figure grid reference for the junction to the north of B in Fig. 1?

[1 mark]

Final answer: Answer

• 017 517

Scale

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

Scale

• Maps in exams will be scaled at either:

  • 1:25,000 (1 cm = 250 m in real life)
  • 1:50,000 (1 cm = 500 m in real life)

• Distance measurement methods:

  • For straight or nearly straight distances:

    • Use a ruler
    • Use the edge of a straight piece of paper

  • Using map scale:

    • Mark distances on a piece of paper using the scale at the map's bottom
    • Lay the marked paper from first to second point to calculate distance

Using scale to measure a straight line

• Measuring curved route distances:

  • Divide the route into segments
  • Rotate and mark the paper in stages to calculate the full distance

• Measuring road routes on the map:

  • Divide the route into straight sections using crosses
  • Use the paper to measure from A to the first cross
  • Rotate the paper, pivoting at the cross to mark the second cross

Using scale to measure curved route distances

Area

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

Area

• The scale of a map is important when accurately calculating area

• Areas can be divided into squares and triangles to make the calculation easier

  • The area of a rectangle = length x width
  • The area of a triangle = 1/2 base x height

• For a map with the scale 1:25,000

• To calculate an area where the length on the map is 4 cm and the width is 2 cm, the calculation is as follows:

  • Length 4 x 25,000 = 100,000 = 1,000 metres
  • Width 2 x 25,000 = 50,000 = 500 meters

• Area in m² = 1000 x 500 = 500,000 meters² or 0.5km²

Bearings

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

Bearings

• Directions on a map should always be given using compass points
• There are 16 compass points

Sixteen Compass Points

• A grid bearing is measured from the grid north at 0°, east at 90°, south at 180°, and west at 270°

• Grid bearings are given using a protractor

  • The 0^º should be pointing north and the centre of the protractor should be 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

Illustration showing how to take a map bearing

• On the map below, B is south-west of A
• The bearing is 280^º

Height

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

Height

• There are three ways to display height:

  • spot height
  • contour lines
  • trigonometrical (trig) 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-metre intervals (distance between the contour line)
  • This means that the height of the land increases by 5 or 10 metres between the lines

• A trigonometrical (trig) station is marked by a small black triangle with a height measurement written next to it

Topography

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

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 *

Cross-sections

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

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

Cross-section on a map

• A piece of paper is then laid along the line and points A and B are marked on
• The contour lines are then marked on each time they cross the paper

Marking on the contour lines

• These figures can then be used to create the cross-section

Cross-section

Key

Spec point — Candidates should be able to: • select, construct and interpret maps using direction, scale, symbols, a key, and other information • extract, interpret, analyse and evaluate information presented on maps • use co-ordinates, latitude and longitude, 4 and 6 figure grid references • give directions using the 16-point compass and bearings from grid north • measure and estimate distances and area • use and interpret gradient, contour lines and spot heights; calculate differences in height • interpret cross-sections and transects.

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

Map key example