Cartographic Skills » Sketch and Thematic Maps

What you'll learn this session

Study time: 30 minutes

The difference between sketch maps and thematic maps
How to create and interpret sketch maps
Different types of thematic maps and their uses
Techniques for representing geographical data visually
How to select appropriate mapping techniques for different data
Real-world applications of cartographic skills

Introduction to Cartographic Skills: Sketch and Thematic Maps

Maps are essential tools for geographers to understand and communicate spatial information. In this session, we'll explore two important types of maps: sketch maps and thematic maps. Both help us visualise geographical data, but they do so in different ways and for different purposes.

Key Definitions:

Cartography: The art and science of making maps.
Sketch Map: A simple, hand-drawn map showing the main features of an area.
Thematic Map: A map that focuses on displaying a specific theme or subject area.
Spatial Distribution: How features or phenomena are arranged across a geographical area.

🗺 Sketch Maps

Sketch maps are simplified representations of an area that highlight key features. They don't need to be perfectly to scale but should show the relative positions of important elements. Sketch maps are useful for fieldwork, quick reference and communicating observations.

📊 Thematic Maps

Thematic maps focus on showing specific data or themes rather than just geographical features. They use various techniques like colours, symbols and patterns to represent data distributions, making complex information easier to understand at a glance.

Creating Effective Sketch Maps

Sketch maps are valuable tools for fieldwork and geographical studies. While they don't need to be artistic masterpieces, they should clearly communicate spatial information.

Elements of a Good Sketch Map

When creating a sketch map, include these essential elements:

📍 Basic Elements

Title
Date
North arrow
Scale (approximate)
Key/legend

🛠 Techniques

Use simple symbols
Label key features
Show relative distances
Include boundary lines
Use consistent symbols

⚠ Common Mistakes

Too much detail
Unclear symbols
Missing labels
No scale reference
Forgetting the north arrow

Practical Example: Urban Fieldwork Sketch Map

When studying urban land use, a sketch map might show:

Main roads and transport routes
Different building types (residential, commercial, industrial)
Green spaces and recreational areas
Key landmarks and services
Boundaries between different land use zones

This helps visualise patterns in urban development and land use that might not be immediately obvious from written notes alone.

Understanding Thematic Maps

Thematic maps are powerful tools for displaying specific geographical data. They help us see patterns, relationships and trends that might be difficult to spot in tables or text.

🌎 Types of Thematic Maps

Choropleth maps: Use different colours or shading to show variation in data across regions (e.g., population density by country)
Isoline maps: Connect points of equal value with lines (e.g., contour lines showing elevation)
Dot maps: Use dots to represent the presence of a feature or quantity
Proportional symbol maps: Use differently sized symbols to represent quantities
Flow maps: Show movement or connections between places

💡 When to Use Each Type

Use choropleth maps for showing variations across defined areas (like countries or counties).

Use isoline maps for continuous data that changes gradually across space (like temperature or rainfall).

Use dot maps when showing the distribution of discrete features or events.

Use proportional symbols when comparing quantities at specific locations.

Use flow maps when showing migration, trade, or other movements between places.

Choropleth Maps in Detail

Choropleth maps are one of the most common thematic maps you'll encounter in geography. They use different colours or shading to represent data values across defined geographical areas.

Creating Effective Choropleth Maps

To create a useful choropleth map:

Choose appropriate data: The data should vary across regions (e.g., population density, income levels, voting patterns).
Select a suitable colour scheme: Use a logical progression of colours or shades (e.g., light to dark).
Create meaningful categories: Divide your data into 4-7 categories that show important variations.
Include a clear legend: Show what each colour represents.
Consider data standardisation: Often data needs to be shown as rates or percentages rather than raw numbers (e.g., people per km² rather than total population).

Case Study Focus: Global Climate Data

Thematic maps are essential for understanding climate patterns. For example, a choropleth map showing average annual rainfall across Africa can reveal:

The wet equatorial regions (dark blue)
The arid Sahara Desert (pale yellow)
The moderate rainfall in coastal regions (medium blue)

This visual representation makes it much easier to identify climate zones and understand how rainfall varies across the continent than looking at tables of rainfall data.

Isoline Maps and Their Applications

Isoline maps connect points of equal value and are particularly useful for showing continuous data that changes gradually across space.

Common Types of Isoline Maps

Contour maps: Show lines of equal elevation (height above sea level)
Isobar maps: Show lines of equal atmospheric pressure
Isotherm maps: Show lines of equal temperature
Isohyet maps: Show lines of equal rainfall

Isoline maps help us understand how values change across space and identify areas of rapid or gradual change. For example, closely spaced contour lines indicate steep slopes, while widely spaced lines show flatter terrain.

Practical Applications of Cartographic Skills

The mapping skills you learn in geography have real-world applications across many fields and situations.

🌐 Real-World Uses

Urban planning: Mapping land use, population density and transport networks
Environmental management: Showing pollution levels, biodiversity hotspots, or conservation areas
Health geography: Mapping disease outbreaks or access to healthcare
Economic development: Visualising income levels, unemployment, or investment
Disaster management: Mapping flood risk zones, evacuation routes, or earthquake impacts

📝 Fieldwork Applications

In geographical fieldwork, you might use:

Sketch maps to record observations during site visits
Choropleth maps to display survey results across different areas
Dot maps to show the locations of specific features you've identified
Flow maps to show pedestrian movement in a shopping area
Proportional symbol maps to compare data between sample sites

Choosing the Right Map for Your Data

Selecting the appropriate mapping technique is crucial for effectively communicating geographical information.

Decision-Making Guide

Ask yourself these questions when deciding which map type to use:

What is the nature of my data? (Continuous or discrete, qualitative or quantitative)
What geographical units am I working with? (Points, lines, areas)
What pattern or relationship am I trying to show? (Distribution, comparison, change over time)
Who is my audience? (Their familiarity with map reading and the subject matter)

Remember that the goal is clear communication. Sometimes the simplest map is the most effective!

Exam Tip: Map Skills Questions

In your iGCSE Geography exam, you might be asked to:

Interpret data from different types of maps
Suggest appropriate mapping techniques for different data sets
Describe patterns shown on thematic maps
Explain the advantages and limitations of different mapping techniques
Draw a simple sketch map based on information provided

Practice these skills regularly with different examples to build your confidence!

Summary: Key Points to Remember

Sketch maps are simplified, hand-drawn representations that highlight key features of an area.
Thematic maps focus on displaying specific data or themes using various visual techniques.
Different types of thematic maps (choropleth, isoline, dot, proportional symbol, flow) are suited to different kinds of data.
All maps should include basic elements like a title, scale, north arrow and legend.
Choosing the right map type depends on your data, purpose and audience.
Cartographic skills have numerous real-world applications in fields ranging from urban planning to disaster management.

🧠 Test Your Knowledge!