Test Your Knowledge Flash Cards 🔒Play Lemonaire 🔒Play Last Stand

Cartographic Skills » Types of Map

What you'll learn this session

Study time: 30 minutes

Cambridge spec: Geographical skills, Cartographic skills

The main types of map and what each one shows
How to read each type, and when it is the best one to use
The strengths and limitations of each type
How to describe a pattern on a map

🔒 Unlock Full Course Content

Unlock This Course

Choosing the right map

There is no single best map. A geographer picks the type of map that suits the question. A walker needs different information from someone studying rainfall across a country. Always check the title and key first, then ask: what does this map show, and what can it not show?

Key terms:

Atlas map: a general map in a book of maps, showing physical features, countries, cities and borders.
Base map: a simple outline map, with coastlines, borders or roads, that data is added to.
Thematic map: a map that shows one theme, such as rainfall or population, instead of everything.
Topographical map: a detailed map of the physical and human features of an area, with contours, roads and buildings.
Sketch map: a simple hand-drawn map, not to scale, showing only the main features.

Maps that show places and features

📖 Atlas maps

Reading: use the key and the index at the back to find places. Use: finding where a country, river or city is. Strength: covers the whole world and many themes. Limitation: small scale, so little local detail.

🌎 Base maps

Reading: look at what has been added on top. Use: plotting your own fieldwork results. Strength: clear and uncluttered. Limitation: shows nothing useful until data is added.

🗺 Topographical maps

Reading: use the key, contours, grid and scale. Use: planning a route, studying relief, finding settlements. Strength: very detailed and accurate. Limitation: crowded, and it gets out of date.

✏ Sketch maps

Reading: check the labels and any annotations. Use: fieldwork and quick exam answers. Strength: fast and shows only what matters. Limitation: not accurate and not to scale.

Maps of different scales

Scale was explained in Grid References, Directions and Distance. Here the point is how scale changes the map. A large-scale map shows a small area in lots of detail. A 1:25 000 map is larger scale than a 1:50 000 map, so it suits a walking route or a town centre, while 1:50 000 suits a wider district. An atlas map is small scale: it shows a big area, such as a continent, in little detail. Both topographical scales are large scale compared with an atlas.

Maps that show data

These are all thematic maps, because each one shows a single theme.

Map	What it shows	How to read it	Best used for	Strength	Limitation
Choropleth	A value for each area, such as each country	Darker shade means a higher value	Patterns are easy to see at a glance	Comparing rates between areas	Hides differences inside each area
Distribution (dot)	Where things are, one dot for a number of items	Clusters show where there are many	Shows spread and clustering clearly	Showing spread and clusters	Dots can overlap, and exact values are hard to read
Isoline	Lines joining places with the same value	Lines close together mean a rapid change	Shows a gradual change across space	Values that change smoothly, such as temperature	Needs many measurements to draw well
Flow line	Movement, such as trade or migration	Width of the line shows the quantity	Shows direction and amount together	Movement of people, goods or traffic	Many lines can cross and become messy
Desire line	Straight lines between a start and an end point	Each line joins an origin to a destination	Shows links between places simply	Links between places, such as commuting	Not the real route taken
Route	The way to get from one place to another, such as a bus or rail line	Follow the line between the stops	Clear and simple for travellers	Planning a journey	Often not to scale, with little else shown
Sphere of influence	The area a place serves, such as a shop or hospital	The boundary shows how far its pull reaches	Shows the area a service draws people from	Showing how far a service reaches	Edges are not sharp, and they change over time

Choropleth and isoline maps in more detail

A choropleth map was met in Global Patterns of Calorie Intake. When you draw one, you must choose classes (groups of values). Use about four to six classes, make them equal in size where you can, and use one colour that gets darker as the value rises, with the key in order. Too few classes hides the pattern. Too many makes the shades impossible to tell apart.

An isoline joins places of equal value. Isotherms join places with the same temperature. Isobars join places with the same air pressure. Where the lines are close together the value changes quickly, and where they are far apart it changes slowly. Contours, from the last lesson, are isolines for height.

Describing a pattern on a map

General trend: say what the overall pattern is, for example "highest in the north and lowest in the south".
Examples with data: name two or three places and quote their values or shade, with units.
Anomalies: point out any place that does not fit the trend.

Describing says what the pattern is. Explaining says why. Keep them separate.

Worked example

A made-up choropleth map shows the percentage of people living in cities. In the west, Country A is 85% and Country B is 80% (both dark). In the east, Country C is 30% (light). Country D is in the west but is only 35% (light). A good description: "Urban population is highest in the west, where Country A is 85% and Country B is 80%, and lowest in the east, where Country C is 30%. Country D is an anomaly because it is in the west but has only 35%." Notice the trend, the data and the anomaly.

Common mistakes

Choosing a flow line map when only the start and end points matter (use a desire line). Reading a choropleth as if every part of a country has the same value. Describing only one place instead of the whole pattern. Forgetting to quote data with units. Treating a sketch map as if it were to scale.

Exam-style question

Fig. 1.1 is a made-up choropleth map showing the percentage of households with internet access in six regions: North 88%, South 85%, East 72%, West 45%, Central 60% and Coast 52%. The darkest shades are the highest percentages.

(a) Identify the type of map shown in Fig. 1.1. [1]

(b) Describe the pattern shown. [3]

(d) Suggest which type of map would be best to show how many people travel from each region to the capital city each day, and why. [2]

(e) Evaluate the usefulness of a choropleth map compared with a dot map for showing where people live. [6]

Model answer

(a) A choropleth map (1)

(b) General trend: access is highest in the north and south and lowest in the west (1). Data: North is 88% and South is 85%, but West is only 45% (1). The Coast, at 52%, is also low (1).

(c) The map gives one value for a whole region (1), so it hides differences inside the region, for example between a city and a village (1).

(d) A flow line map (1), because the width of each line can show how many people travel along each route (1).

(e) Level 3 (5-6 marks): A choropleth map is useful because it gives a value for every region, so the pattern, such as high values in the north, is easy to see at a glance. However it hides how people are spread inside each region, and a large region with few people can look as important as a small one with many. A dot map is better for showing where people live, because each dot stands for a number of people, so it shows clusters in cities and empty areas. Its weakness is that dots can overlap in crowded places and exact numbers are hard to read. Overall the dot map is more useful for where people live, and the choropleth is better for comparing percentages between regions.

Exam tip

In a "describe the pattern" question, always give a trend, then data with units from the map, then any anomaly.

Test Your Knowledge