CTEVT📚 Cartography – Chapter 4: Graphic Variables (Full Chapter + Free PDF + Illustrations)
🚀 What are Graphic Variables?
Have you ever wondered how maps communicate information so effectively? Why are rivers shown in blue, roads with different line widths, and cities with various symbols? The answer lies in Graphic Variables.
Graphic variables are the visual elements used by cartographers to represent different types of geographic information on maps. By changing the size, shape, colour, orientation, texture, and value of symbols, maps become easier to understand and interpret.
Graphic variables are the foundation of map symbolization and play a vital role in both conventional and digital cartography.
📌 Overview
Graphic variables are the visual characteristics of map symbols that help distinguish one feature from another.
For example:
- Thick roads represent highways.
- Blue colour represents water bodies.
- Green colour represents forests.
- Large circles may represent large cities.
- Dark colours often indicate higher values.
Without graphic variables, maps would be confusing and difficult to interpret.
"Graphic variables are the visual language of maps."
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📚 What is Covered in Chapter 4
✔ Definition of Graphic Variables
✔ Importance of Graphic Variables
✔ Concept of Visual Perception
✔ Types of Graphic Variables
✔ Applications in Cartography
✔ Examples of Graphic Variables
✔ 4.1 Definition of Graphic Variables
Graphic variables are the visual properties of symbols used to represent geographical information on maps.
These variables help users distinguish between different features and understand map information quickly.
Simple Definition
Graphic variables are the visual characteristics used to represent map features.
Definition by Jacques Bertin
French cartographer Jacques Bertin (1967) introduced the concept of graphic variables.
According to Bertin,
Graphic variables are the visual properties used to differentiate symbols and communicate geographic information effectively.
His theory remains the foundation of modern cartographic design.
✔ Objectives of Graphic Variables
Graphic variables are used to:
- Improve map readability.
- Differentiate map features.
- Communicate spatial information effectively.
- Represent quantitative and qualitative data.
- Enhance map appearance.
- Reduce confusion.
- Improve visual hierarchy.
✔ Importance of Graphic Variables
Graphic variables are essential because they:
1. Improve Communication
They make geographic information easier to understand.
2. Differentiate Features
Different colours, sizes, and shapes distinguish different objects.
Example:
- River → Blue Line
- Road → Black Line
- Forest → Green Area
3. Improve Visual Hierarchy
Important features appear more prominent than less important ones.
Example:
- National Highway → Thick Line
- Local Road → Thin Line
4. Simplify Complex Information
Large amounts of geographic data can be represented simply.
5. Improve Map Attractiveness
Proper graphic variables make maps visually appealing.
6. Reduce Misinterpretation
Standard symbols reduce confusion among users.
7. Support Decision Making
Clear maps help planners, engineers, and administrators make informed decisions.
✔ Characteristics of Good Graphic Variables
A good graphic variable should be:
- Simple
- Clear
- Easy to recognize
- Consistent
- Scientifically meaningful
- Visually balanced
- Suitable for the map purpose
✔ Applications of Graphic Variables
Graphic variables are used in:
- Topographic Maps
- Thematic Maps
- GIS Mapping
- Urban Planning
- Navigation Maps
- Land Use Maps
- Population Maps
- Geological Maps
- Weather Maps
📝 Key Points for Examination
Remember:
- Graphic variables are visual properties of map symbols.
- They improve communication and map interpretation.
- Jacques Bertin introduced the concept of graphic variables.
- Graphic variables are used in almost every type of map.
✔ 4.2 Concept of Visual Perception
Visual perception is the process by which the human brain receives, interprets, and understands visual information.
In cartography, visual perception explains how map users recognize symbols, colours, patterns, and shapes.
A well-designed map takes advantage of human visual perception to communicate information efficiently.
Why Visual Perception is Important
Good visual perception helps users:
- Identify symbols quickly.
- Compare different features.
- Understand spatial patterns.
- Interpret thematic information.
- Locate important objects easily.
Factors Affecting Visual Perception
Size
Larger symbols attract more attention.
Colour
Bright colours are noticed before dull colours.
Shape
Different shapes help distinguish different categories.
Contrast
High contrast improves readability.
Example:
Black text on a white background.
Position
Objects placed at the centre are often noticed first.
Pattern
Repeated patterns help identify similar features.
✔ Principles of Visual Perception in Cartography
Good map design follows these principles:
Simplicity
Avoid unnecessary symbols.
Balance
Arrange map elements evenly.
Emphasis
Important features should stand out.
Harmony
Colours and symbols should work together.
Unity
All map elements should appear related.
Legibility
Symbols and labels should be easy to read.
✔ Types of Graphic Variables
According to Jacques Bertin, there are seven major graphic variables.
1. Size
Size refers to the dimensions of a symbol.
Large symbols indicate greater importance or quantity.
Example:
- Large city → Large circle
- Small village → Small circle
2. Shape
Different shapes distinguish different categories.
Examples:
- Circle → Town
- Square → Building
- Triangle → Mountain Peak
- Star → Capital City
3. Value (Lightness)
Value refers to the lightness or darkness of a colour.
Dark colours often represent higher values.
Light colours represent lower values.
Example:
Population Density Map
- Light Colour → Low Population
- Dark Colour → High Population
4. Colour (Hue)
Hue refers to different colours.
Examples:
- Blue → Water
- Green → Forest
- Brown → Contours
- Black → Buildings
- Red → Major Roads
5. Orientation
Orientation refers to the direction of symbols or patterns.
Example:
Different line directions may represent different geological formations or land use patterns.
6. Texture (Pattern)
Texture is created by repeating symbols or patterns.
Examples:
- Dense dots → Dense forest
- Sparse dots → Grassland
7. Position
Position refers to the location of a symbol on the map.
Correct positioning ensures accurate representation of geographic features.
✔ Summary of Graphic Variables
| Graphic Variable | Represents | Example |
|---|---|---|
| Size | Quantity/Importance | Large city vs. small village |
| Shape | Category | Circle, square, triangle |
| Value | Magnitude | Dark vs. light shading |
| Colour (Hue) | Feature type | Blue river, green forest |
| Orientation | Direction | Pattern angles |
| Texture | Density/Pattern | Dense vs. sparse dots |
| Position | Location | Exact map coordinates |
✔ Uses of Graphic Variables
Graphic variables are widely used in:
- Topographic Maps
- Cadastral Maps
- GIS
- Remote Sensing
- Land Use Mapping
- Transportation Maps
- Environmental Mapping
- Disaster Management
- Census Maps
📝 Key Points for Examination (Part 2)
Remember:
- Visual perception is how people understand map symbols.
- Jacques Bertin introduced the seven graphic variables.
-
The seven graphic variables are:
- Size
- Shape
- Value
- Colour (Hue)
- Orientation
- Texture
- Position
- Graphic variables improve map communication, readability, and interpretation.
✔ Applications of Graphic Variables
Graphic variables are applied in almost every type of map to improve communication and readability.
1. Topographic Maps
- Different colours distinguish forests, rivers, roads, and settlements.
- Different line widths represent roads of different importance.
- Contours are represented using brown lines.
2. Thematic Maps
Graphic variables are extensively used to represent statistical data.
Examples:
- Population Density
- Rainfall Distribution
- Literacy Rate
- Agricultural Production
- Land Use
3. Cadastral Maps
Graphic variables help distinguish:
- Parcel Boundaries
- Roads
- Buildings
- Survey Control Points
4. Geological Maps
Different colours and patterns represent different rock formations.
5. Land Use Maps
Different colours represent:
- Forest
- Agriculture
- Settlement
- Water Bodies
- Grassland
6. Transportation Maps
Graphic variables distinguish:
- National Highways
- Local Roads
- Railways
- Airports
7. GIS and Digital Cartography
Modern GIS software uses graphic variables to create dynamic and interactive maps.
Software includes:
- QGIS
- ArcGIS
- AutoCAD Map
- Google Earth
🌍 Practical Applications
Practical 1: Identify Graphic Variables
Take a Topographic Map of Nepal and identify examples of the following:
- Size
- Shape
- Colour
- Value
- Texture
- Orientation
- Position
Practical 2: Design a Simple Symbol Set
Draw symbols for the following features using different graphic variables:
- School
- Hospital
- Temple
- Bridge
- Forest
- River
- Road
Practical 3: Land Use Mapping
Prepare a simple Land Use Map of your locality using appropriate colours and symbols for:
- Settlement
- Agriculture
- Forest
- Water Bodies
- Roads
Practical 4: GIS Exercise
Using QGIS or ArcGIS, create a thematic map and apply:
- Different colours
- Different symbol sizes
- Labels
- Patterns
Observe how graphic variables improve map readability.
Practical 5: Visual Perception Exercise
Compare two maps:
- One with proper colours and symbols.
- One with poor colours and symbol selection.
Write five differences in readability and interpretation.
📂 Download Free PDF Notes – Chapter 4: Graphic Variables
Perfect for:
✅ CTEVT exam preparation
✅ Lab assignments on symbolization
✅ QGIS and ArcGIS practice
🔽 [Download Notes – Chapter 4: Graphic Variables (PDF)]
🧮 Practice Questions for Students
🧾 Practice Questions for Students
Short Questions
- Define graphic variables.
- Who introduced the concept of graphic variables?
- Define visual perception.
- Why are graphic variables important?
- List the seven graphic variables.
- What is meant by "value" in graphic variables?
- Differentiate between colour and value.
- Define texture as a graphic variable.
- What is orientation?
- State four applications of graphic variables.
📚 Long / Analytical Questions
1.Define graphic variables and explain their importance in cartography.
2.Explain the concept of visual perception with suitable examples.
3.Describe the seven graphic variables introduced by Jacques Bertin.
4.Discuss the applications of graphic variables in map design.
5.Explain how graphic variables improve communication and map interpretation.
6.Differentiate between:
(a) Colour and Value
(b) Shape and Size
(c) Texture and Orientation
7.Write short notes on:
- Size
- Shape
- Colour
- Texture
- Orientation
- Position
🎯 Cartography Chapter 4 – Graphic Variables (20 Exam-Oriented MCQs)
1. Graphic variables are used to:
A. Measure land
B. Represent map features visually
C. Calculate coordinates
D. Print maps
2. The concept of graphic variables was introduced by:
A. Robinson
B. Jacques Bertin
C. Mercator
D. Ptolemy
3. Which of the following is NOT a graphic variable?
A. Shape
B. Size
C. Latitude
D. Colour
4. Which graphic variable represents quantity most effectively?
A. Shape
B. Size
C. Orientation
D. Texture
5. Blue colour is generally used for:
A. Roads
B. Forests
C. Water Bodies
D. Buildings
6. Which graphic variable represents different categories?
A. Shape
B. Value
C. Position
D. Size
7. Dark and light shades represent:
A. Orientation
B. Value
C. Shape
D. Texture
8. Texture is created by:
A. Colour only
B. Repeated symbols or patterns
C. Scale
D. Coordinates
9. Which principle helps users understand maps easily?
A. Visual Perception
B. Projection
C. Surveying
D. Digitization
10. Orientation refers to:
A. Symbol colour
B. Symbol direction
C. Symbol size
D. Symbol position
11. Which graphic variable indicates the exact location of a feature?
A. Position
B. Colour
C. Shape
D. Value
12. Which map type frequently uses graphic variables?
A. Topographic Map
B. Thematic Map
C. Cadastral Map
D. All of the above
13. Green colour usually represents:
A. Rivers
B. Roads
C. Forests
D. Buildings
14. Large circles on a map generally represent:
A. Small villages
B. Large cities
C. Rivers
D. Mountains
15. Which of the following improves map readability?
A. Graphic Variables
B. Projection Errors
C. Distortion
D. Random Symbols
16. GIS software mainly uses:
A. Graphic Variables
B. Survey Chains
C. Plane Tables
D. Compass Traverses
17. Which graphic variable distinguishes highways from local roads?
A. Size (Line Width)
B. Shape
C. Texture
D. Position
18. Which is NOT a principle of good visual perception?
A. Balance
B. Unity
C. Confusion
D. Simplicity
19. Which branch of cartography heavily relies on graphic variables?
A. Digital Cartography
B. Thematic Cartography
C. Topographic Cartography
D. All of the above
20. The main purpose of graphic variables is to:
A. Beautify maps only
B. Improve visual communication
C. Increase paper size
D. Replace map projections
✅ Answer Key
| Q.No | Answer | Q.No | Answer |
|---|---|---|---|
| 1 | B | 11 | A |
| 2 | B | 12 | D |
| 3 | C | 13 | C |
| 4 | B | 14 | B |
| 5 | C | 15 | A |
| 6 | A | 16 | A |
| 7 | B | 17 | A |
| 8 | B | 18 | C |
| 9 | A | 19 | D |
| 10 | B | 20 | B |
🏆 Your Score
| Score | Performance |
|---|---|
| 18–20 | 🌟 Graphic Variables Expert |
| 15–17 | 🎯 Exam Ready |
| 10–14 | 👍 Good – Revise Once |
| Below 10 | 📚 Needs More Practice |
💡 Study Tips
- Memorize Jacques Bertin and the seven graphic variables.
- Remember the difference between colour (hue) and value (lightness/darkness).
- Practice identifying graphic variables from topographic maps.
- Learn which variables are best for qualitative and quantitative data.
- Practice map symbol design using different colours, sizes, and shapes.
🎯 Lessons Learned
After completing this chapter, you should be able to:
✅ Define graphic variables.
✅ Explain visual perception in cartography.
✅ Identify and explain the seven graphic variables.
✅ Apply graphic variables in map design.
✅ Understand the importance of graphic variables in conventional and digital cartography.
📖 Frequently Asked Viva Questions
- What are graphic variables?
- Who introduced the concept of graphic variables?
- Define visual perception.
- Why are graphic variables important in cartography?
- Name the seven graphic variables.
- Differentiate between colour and value.
- What is the purpose of texture in map design?
- How does size represent quantitative information?
- Give practical applications of graphic variables.
- Explain the role of graphic variables in GIS and digital cartography.
📘 Explore More from Cartography
📚 Chapter 1: Introduction – Download PDF
📚 Chapter 2: Map – Download PDF
📚 Chapter 3: Branches of Cartography – Download PDF
📚 Chapter 4: Graphic Variables – Download PDF
📚 Chapter 5: Map Projection – Download PDF
📚 Chapter 6: Map Sheet Numbering – Download PDF
📚 Chapter 7: Generalization – Download PDF
📚 Chapter 8: Relief Representation – Download PDF
📚 Chapter 9: Color – Download PDF
📚 Chapter 10: Digital Cartography – Download PDF
📚 Chapter 11: Map Reproduction – Download PDF
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