Cartographic Skills » Different Scale Maps

What you'll learn this session

Study time: 30 minutes

What map scales are and how they work
How to read and interpret different scale maps
How to calculate distances using map scales
The advantages and limitations of small and large scale maps
How to select appropriate map scales for different geographical purposes
Practical skills for working with maps of different scales

Introduction to Map Scales

Maps are like miniature versions of the real world. But to be useful, we need to know exactly how miniature they are! That's where map scales come in. They tell us the relationship between distances on the map and distances in the real world.

Key Definitions:

Map Scale: The ratio between distance on a map and the corresponding distance on the ground.
Large Scale Map: Shows a small area in great detail (e.g., 1:10,000).
Small Scale Map: Shows a large area with less detail (e.g., 1:1,000,000).
Scale Bar: A line marked with distances to help measure real-world distances on a map.
Representative Fraction (RF): Scale shown as a ratio or fraction (e.g., 1:50,000 or 1/50,000).

📏 Understanding Map Scales

Map scales are usually shown in three ways:

Representative Fraction: 1:25,000 means 1 cm on the map equals 25,000 cm (250 m) on the ground
Statement Scale: "1 cm to 250 m" or "1 inch to 1 mile"
Scale Bar: A line marked with distances for direct measurement

🔍 Large vs Small Scale

This can be confusing! Remember:

Large Scale = Small Area + More Detail
(1:10,000 shows a neighbourhood)
Small Scale = Large Area + Less Detail
(1:1,000,000 shows a country)

Think of it this way: the smaller the second number, the larger the scale!

Common Map Scales and Their Uses

🏠 Large Scale

1:10,000 - 1:25,000

Town plans
Local hiking routes
Detailed fieldwork
Site planning

Shows buildings, paths, small streams and individual features

🌳 Medium Scale

1:50,000 - 1:250,000

Ordnance Survey maps
Regional planning
Road maps
Hiking and outdoor activities

Shows roads, settlements, landforms and major features

🌎 Small Scale

1:1,000,000+

Country and world maps
Atlas pages
Climate maps
Population distribution

Shows major cities, country borders and broad patterns

Calculating Distances Using Map Scales

Being able to work out real-world distances from maps is an essential geographical skill that you'll need for your exams and fieldwork.

📊 Step-by-Step Method

Measure the distance on the map in centimetres
Note the scale (e.g., 1:50,000)
Multiply your measurement by the scale number
Convert to appropriate units (km, m)

Example: If a route on a 1:50,000 map measures 6 cm:

6 cm × 50,000 = 300,000 cm = 3,000 m = 3 km

📝 Using Scale Bars

A quicker method for estimating distances:

Use a piece of paper to mark the distance
Compare this to the scale bar
Read off the approximate distance

This is especially useful for curved routes - mark segments on your paper edge and add them up!

Advantages and Limitations of Different Scale Maps

👍 Large Scale Maps (1:10,000 - 1:50,000)

Advantages:

Show detailed features like buildings, paths and small streams
Good for navigation and fieldwork
Useful for local planning and detailed studies
Allow precise distance measurements

Limitations:

Cover only small areas
Can't show regional patterns or connections
Often need multiple sheets for wider studies
Can be overwhelming with too much detail

👎 Small Scale Maps (1:250,000+)

Advantages:

Show large areas like countries or continents
Good for seeing patterns and distributions
Useful for studying regional geography
Show connections between distant places

Limitations:

Lack detail for local features
Less accurate for measuring short distances
Features must be generalised or omitted
Not suitable for navigation in unfamiliar areas

Choosing the Right Map Scale

Selecting the appropriate map scale is crucial for geographical investigations. The right scale depends on what you're studying and why.

🏡 Local Studies

Use large scale maps (1:10,000 - 1:25,000)

Urban land use surveys
River channel studies
Coastal erosion features
Settlement patterns
Microclimate investigations

🌃 Regional Studies

Use medium scale maps (1:50,000 - 1:250,000)

Transport networks
River basin management
Tourism impacts
Urban-rural fringe
Regional economic development

🌏 Global Studies

Use small scale maps (1:1,000,000+)

Climate zones
Population distribution
International migration
Biome distribution
Global development patterns

Case Study Focus: Ordnance Survey Maps

Ordnance Survey (OS) maps are the UK's official mapping agency and produce maps at different scales:

OS Explorer (1:25,000) - Orange covers, show footpaths, field boundaries and detailed terrain. Perfect for hiking and detailed fieldwork.
OS Landranger (1:50,000) - Pink covers, show roads, settlements and landforms. Good for regional planning and general navigation.
OS Road Maps (1:250,000) - Show major roads and settlements. Useful for driving and understanding regional connections.

OS maps use standardised symbols and a National Grid reference system, making them invaluable for geographical studies in the UK. Many iGCSE Geography questions use OS map extracts, so practising with these maps is essential!

Practical Skills for Working with Different Scale Maps

🛠 Essential Map Skills

For your iGCSE exams, you should be able to:

Convert between different types of scales
Calculate real-world distances and areas
Compare features across maps of different scales
Select appropriate scales for specific purposes
Understand how detail changes with scale
Recognise distortion in very small scale maps

⚠ Common Mistakes to Avoid

Confusing large and small scale terminology
Forgetting to convert units when calculating distances
Using inappropriate scales for your study purpose
Not considering the date of the map (features change!)
Assuming all maps use the same symbols
Overlooking the importance of the map's legend/key

Summary: Choosing the Right Map for the Job

Understanding different scale maps is all about selecting the right tool for your geographical investigation. Remember these key points:

Large scale maps (1:10,000 - 1:50,000) show small areas in great detail
Small scale maps (1:250,000+) show large areas with less detail
The scale determines what features can be shown and how accurately
Always consider your purpose when selecting a map scale
Different geographical investigations require different scales
Being able to work across scales is an important geographical skill

In your iGCSE exam, you might be asked to select an appropriate map scale for a particular study, explain the advantages of different scales, or calculate distances using scale information. Practise these skills regularly with different maps to build your confidence!

🧠 Test Your Knowledge!