CTEVT 📚 Cartography – Chapter 5: Map Projection (Full Chapter + Free PDF + Diagrams & Nepal Examples)
🗺️ Have you ever wondered how we project the curved surface of the Earth onto a flat map without distorting it?
🚀 What is a Map Projection?
The Earth is nearly spherical (or more accurately, an oblate spheroid), but maps are drawn on flat surfaces such as paper or computer screens. Since a curved surface cannot be represented perfectly on a flat plane without distortion, map projections are used.
A map projection is a mathematical method of transforming the curved surface of the Earth onto a flat surface. Every map projection introduces some distortion in shape, area, distance, or direction, but different projections are designed to minimise specific types of distortion depending on their intended use.
Map projections are essential in surveying, cartography, GIS, navigation, engineering, and remote sensing.
📌 Overview
Map projection is one of the most important topics in cartography because it provides the method for representing the Earth's curved surface on a plane.
Different projections are designed for different purposes:
- Navigation
- Topographic Mapping
- National Mapping
- Weather Mapping
- World Maps
- GIS Applications
Since no projection can preserve all map properties simultaneously, the choice of projection depends on the purpose of the map.
"A map projection is the systematic transformation of locations on the Earth's curved surface to corresponding locations on a flat map."
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📚 What’s Covered in Chapter 5: Map Projection
✔ Definition of Map Projection
✔ Need for Map Projection
✔ Developable Surfaces
✔ Classification of Map Projections
✔ Properties of Map Projections
✔ Cylindrical Projection
✔ Conical Projection
✔ Azimuthal Projection
✔ Applications of Different Projections
✔ 5.1 Definition of Map Projection
A map projection is the mathematical process of representing the Earth's curved surface on a flat map.
It establishes a relationship between the latitude and longitude on the globe and the coordinates on a flat map.
Simple Definition
Map projection is the method of transferring the Earth's curved surface onto a flat surface.
Definition (Technical)
A map projection is a systematic mathematical transformation of geographic coordinates (latitude and longitude) into plane coordinates (x and y).
✔ Need for Map Projection
Since the Earth is curved, it is impossible to flatten its surface without introducing distortion.
Map projection is required because:
1. To Represent the Curved Earth on a Flat Surface
The Earth cannot be unfolded without stretching, compressing, or tearing.
2. To Prepare Accurate Maps
Surveying, engineering, and planning require maps that represent the Earth's surface systematically.
3. To Support Distance and Area Measurement
Proper projections allow distances and areas to be measured with acceptable accuracy.
4. To Minimise Distortion
Different projections minimise distortion in:
- Area
- Shape
- Distance
- Direction
5. To Support GIS and GPS
Digital mapping systems require map projections for storing and analysing spatial data.
6. For Navigation
Marine and air navigation depend on suitable map projections.
✔ Why Can't a Globe Be Used Instead of a Map?
Although a globe represents the Earth accurately, it has several limitations:
- Difficult to carry
- Cannot show detailed local areas
- Difficult to measure accurately
- Cannot display large-scale engineering plans
- Not suitable for GIS analysis
Therefore, maps and map projections are essential.
✔ Developable Surfaces
A developable surface is a geometric surface that can be unfolded into a flat plane without stretching or tearing.
In cartography, three developable surfaces are commonly used:
- Cylindrical Surface
- Conical Surface
- Plane (Azimuthal) Surface
These surfaces form the basis of most map projections.
1. Cylindrical Surface
Imagine wrapping a cylinder around the Earth.
The Earth's surface is projected onto the inside or outside of the cylinder.
After projection, the cylinder is cut and unrolled into a flat map.
Characteristics
- Meridians are straight and equally spaced.
- Parallels are horizontal lines.
- Distortion increases toward the poles.
Suitable For
- Equatorial regions
- World maps
- Marine navigation
2. Conical Surface
Imagine placing a cone over the Earth so that it touches one or two parallels.
The Earth's surface is projected onto the cone.
The cone is then cut and opened into a flat map.
Characteristics
- Meridians converge towards the pole.
- Parallels are arcs of circles.
- Distortion is least near the standard parallel(s).
Suitable For
- Mid-latitude countries
- National mapping
- Topographic mapping
3. Plane (Azimuthal) Surface
A flat plane touches the Earth at one point or cuts through it.
The Earth's surface is projected onto this plane.
Characteristics
- Accurate around the point of contact.
- Distortion increases away from the centre.
- Directions from the centre are usually accurate.
Suitable For
- Polar regions
- Aviation
- Radio communication
- Hemisphere maps
✔ Classification of Map Projections
Map projections can be classified in several ways.
A. According to Developable Surface
- Cylindrical Projection
- Conical Projection
- Azimuthal (Plane) Projection
B. According to Property Preserved
Equal Area Projection
Preserves area.
Examples:
- Albers Equal Area
- Lambert Equal Area
Applications:
- Population maps
- Land use maps
- Statistical maps
Conformal Projection
Preserves shape and local angles.
Examples:
- Mercator Projection
- Lambert Conformal Conic
Applications:
- Navigation
- Topographic maps
- Engineering
Equidistant Projection
Preserves distance from one or more selected points or lines.
Applications:
- Airline routes
- Distance measurement
True Direction (Azimuthal) Projection
Preserves direction from the centre.
Applications:
- Air navigation
- Radio communication
Compromise Projection
Balances distortion without preserving any single property perfectly.
Examples:
- Robinson Projection
- Winkel Tripel Projection
Applications:
- World Atlas Maps
✔ Properties of Map Projections
Every map projection attempts to preserve one or more of the following properties:
Shape (Conformality)
Maintains the correct shape of small features.
Example:
Buildings appear with correct angles.
Area (Equivalence)
Maintains correct relative areas.
Useful for:
- Land use maps
- Population density maps
- Resource distribution maps
Distance (Equidistance)
Maintains true distances along certain lines or from selected points.
Direction (Azimuth)
Maintains true direction from a reference point.
Useful in:
- Air navigation
- Marine navigation
📝 Key Points for Examination
Remember:
- A map projection transforms the Earth's curved surface onto a flat map.
- No projection can preserve shape, area, distance, and direction simultaneously.
-
Three basic developable surfaces are:
- Cylindrical
- Conical
- Plane (Azimuthal)
-
Major projection properties are:
- Equal Area
- Conformal
- Equidistant
- True Direction
- Compromise
🧩 Properties of Map Projections
Every projection preserves some properties while distorting others.
| Property | Meaning | Projection Type Preserving It |
|---|---|---|
| Area (Equivalent) | Maintains true area | Equal-area projections |
| Shape (Conformal) | Maintains local angles and shape | Conformal projections |
| Distance (Equidistant) | Preserves true distance along specific lines | Equidistant projections |
| Direction (Azimuthal) | Maintains correct bearings from a central point | Azimuthal projections |
🧠 No single projection can preserve all properties simultaneously — the choice depends on map purpose.
🗺️ Classification of Map Projections
Map projections are generally classified based on projection surface and method of projection.
🧭 1️⃣ Cylindrical Projection
In this projection, the Earth’s surface is projected onto a cylinder that touches or cuts the globe.
🧩 Types:
- Simple Cylindrical (Equirectangular) – equally spaced grid
- Mercator Projection – conformal; preserves shape, used for navigation
- Transverse Mercator – used for narrow zones along meridians (basis for UTM/MUTM)
📍 Uses: Navigation, equatorial regions, GIS base maps.
🗻 2️⃣ Conical Projection
The Earth’s surface is projected onto a cone that touches or intersects the globe along one or two standard parallels.
🧩 Types:
- Simple Conical (One Standard Parallel)
- Lambert Conformal Conic (Two Standard Parallels)
📍 Uses: Mid-latitude countries and topographic maps.
Example: Used in India and parts of Europe.
🧊 3️⃣ Azimuthal (Planar) Projection
The projection surface is a flat plane that touches the globe at one point (usually poles or center).
🧩 Types:
- Stereographic – conformal
- Orthographic – perspective (as seen from space)
- Gnomonic – shows great circles as straight lines
📍 Uses: Polar regions, air route planning, and seismic mapping.
🌍 4️⃣ Miscellaneous Projections
Other projections include:
- Polyconic Projection – used for large-scale topographic maps
- Bonne’s Projection – equal-area heart-shaped map
- Sinusoidal Projection – equal-area for world maps
🧠 Nepal’s National Projection System – MUTM
🇳🇵 Nepal officially uses the Modified Universal Transverse Mercator (MUTM) projection system for national mapping and GIS datasets.
🧮 Key Details:
- Projection Type: Transverse Mercator (Conformal)
- Datum: WGS 84 or Everest 1830 (local)
- Zones Used:
- MUTM Zone 45 – 84°E to 87°E
- MUTM Zone 46 – 87°E to 90°E
- Central Meridians: 85°30′E (Zone 45) and 88°30′E (Zone 46)
- Unit: Meters (Eastings and Northings)
📍 Application: Used in Survey Department topographic maps, cadastral mapping, and GIS layers for consistent coordinate referencing.
✔ 5.2 Types of Map Projections (Detailed)
The three fundamental types of map projections are based on the developable surface used for projecting the Earth's surface.
- Cylindrical Projection
- Conical Projection
- Azimuthal (Plane) Projection
Each has different characteristics, advantages, disadvantages, and applications.
✔ Cylindrical Projection
In a cylindrical projection, the Earth is imagined to be enclosed by a cylinder touching the globe along the Equator (or intersecting it).
The geographical features are projected onto the cylinder, which is then cut along a line and unrolled into a flat map.
Characteristics
- Meridians are straight, parallel, and equally spaced.
- Parallels are straight lines intersecting meridians at right angles.
- Distortion increases towards the poles.
- The Equator has minimum distortion.
Advantages
- Easy to construct.
- Directions are accurate in conformal cylindrical projections (e.g., Mercator).
- Suitable for equatorial regions.
- Widely used for marine navigation.
Disadvantages
- Polar regions appear greatly enlarged.
- Area distortion increases toward the poles.
- Not suitable for mapping polar regions.
Applications
- World maps
- Marine navigation
- Weather maps
- Equatorial region mapping
Example: Mercator Projection
The Mercator Projection is the most famous cylindrical projection.
Features
- Conformal (preserves shape locally)
- Rhumb lines (lines of constant bearing) appear as straight lines.
- Excellent for marine navigation.
- Greatly exaggerates the size of Greenland, Antarctica, and other high-latitude regions.
✔ Conical Projection
A conical projection is formed by placing a cone over the Earth so that it touches one or two standard parallels.
The projected cone is cut and unfolded into a flat surface.
Characteristics
- Meridians are straight lines meeting at the apex.
- Parallels are arcs of concentric circles.
- Distortion is least along the standard parallel(s).
- Distortion increases away from the standard parallel.
Advantages
- Good accuracy for mid-latitude regions.
- Suitable for areas with greater east-west extent.
- Less distortion than cylindrical projections in mid-latitudes.
Disadvantages
- Not suitable for world maps.
- Distortion increases away from standard parallels.
- Not appropriate for equatorial and polar regions.
Applications
- National topographic maps
- Weather maps
- State or provincial maps
- Road maps
- Engineering mapping
Example: Lambert Conformal Conic Projection
Features
- Conformal projection
- Preserves shape and angles.
- Commonly used for aeronautical charts.
- Widely used in national mapping agencies.
✔ Azimuthal (Plane) Projection
An azimuthal projection is created by placing a flat plane so that it touches the Earth at one point (or cuts through it).
The Earth's surface is then projected onto the plane.
Characteristics
- Accurate at the centre of projection.
- Distortion increases away from the centre.
- Directions from the centre are usually correct.
- Suitable for circular maps.
Advantages
- Accurate direction from the centre.
- Excellent for polar mapping.
- Useful for radio and air navigation.
Disadvantages
- High distortion near the edges.
- Limited coverage area.
- Not suitable for mapping the entire world.
Applications
- Polar maps
- Aviation
- Radio communication
- Satellite coverage maps
Example: Polar Azimuthal Projection
Features
- Plane touches the North or South Pole.
- Meridians radiate from the centre.
- Parallels form concentric circles.
- Frequently used for Arctic and Antarctic maps.
✔ Comparison of the Three Major Projections
| Feature | Cylindrical | Conical | Azimuthal |
|---|---|---|---|
| Developable Surface | Cylinder | Cone | Plane |
| Best Region | Equatorial | Mid-latitudes | Polar Regions |
| Meridians | Straight & Parallel | Straight & Converging | Radiating from Centre |
| Parallels | Straight | Circular Arcs | Concentric Circles |
| Distortion | High near poles | High away from standard parallels | High away from centre |
| Common Example | Mercator | Lambert Conformal Conic | Polar Azimuthal |
✔ Selection of a Suitable Map Projection
The choice of a map projection depends on:
Purpose of the Map
Different purposes require different projections.
Example:
- Navigation → Mercator Projection
- Population Map → Equal Area Projection
- Aviation → Azimuthal Projection
Area Covered
- World → Cylindrical or Compromise Projection
- Country → Conical Projection
- Polar Region → Azimuthal Projection
Property to Preserve
Depending on the requirement:
- Shape → Conformal Projection
- Area → Equal Area Projection
- Distance → Equidistant Projection
- Direction → Azimuthal Projection
Geographic Location
- Equatorial regions → Cylindrical
- Mid-latitudes → Conical
- Polar regions → Azimuthal
✔ Advantages of Map Projections
- Represent the Earth's curved surface on a flat map.
- Support surveying and engineering.
- Enable GIS and spatial analysis.
- Facilitate navigation.
- Help prepare thematic and topographic maps.
- Allow measurement of distance, area, and direction.
✔ Limitations of Map Projections
- No projection is completely distortion-free.
- Shape, area, distance, and direction cannot all be preserved simultaneously.
- Different projections are needed for different purposes.
- Incorrect projection selection may lead to inaccurate analysis.
✔ Applications of Map Projections
Surveying
- Topographic map preparation
- National mapping
- Engineering surveys
GIS
- Spatial database management
- Overlay analysis
- Georeferencing
- Spatial modelling
Remote Sensing
- Satellite image correction
- Orthorectification
- Image mosaicking
Navigation
- Marine navigation
- Air navigation
- GPS mapping
Urban Planning
- Land use planning
- Utility mapping
- Infrastructure development
Disaster Management
- Flood hazard maps
- Earthquake risk maps
- Landslide susceptibility maps
🌍 Practical Applications
Practical 1: Identify Projection Type
Collect three different maps (world map, Nepal map, and polar map). Identify the projection used and justify your answer.
Practical 2: Compare Distortion
Observe a Mercator world map and compare the sizes of:
- Greenland
- Africa
- Antarctica
Write how projection affects the apparent size of these regions.
Practical 3: Globe vs Flat Map
Compare a globe with a world map and identify at least five differences in terms of:
- Shape
- Area
- Distance
- Direction
- Distortion
Practical 4: GIS Exercise
Using QGIS or ArcGIS:
- Load a world map.
- Change its Coordinate Reference System (CRS) to different projections (e.g., Mercator and Lambert Conformal Conic).
- Observe and record the changes in shape and size.
Practical 5: Draw Developable Surfaces
Draw neat sketches showing:
- Cylinder around the Earth
- Cone around the Earth
- Plane touching the Earth
Label the point or line of contact and explain which regions each projection is best suited for.
📂 Download Free PDF Notes – Chapter 5: Map Projection
📂 Download Free PDF Notes – Chapter 5: Map ProjectionPerfect for:
✅ CTEVT exam preparation
✅ Practical mapping and GIS use
✅ NEC License projection-related questions
🔽 [Download Notes – Chapter 5: Map Projection (PDF)]
🧾 Practice Questions
Short Questions
- Define map projection.
- Why is map projection necessary?
- What is a developable surface?
- Name the three basic developable surfaces.
- Define cylindrical projection.
- What is a conical projection?
- Define azimuthal projection.
- What is a conformal projection?
- What is an equal-area projection?
- State four applications of map projections.
📚 Long / Analytical Questions
- Define map projection and explain its importance.
- Explain the need for map projections.
- Describe the three developable surfaces used in map projections.
- Compare cylindrical, conical, and azimuthal projections with suitable diagrams.
- Explain the different properties of map projections.
- Discuss the advantages and limitations of map projections.
- Explain the applications of map projections in surveying, GIS, and remote sensing.
-
Write short notes on:
- Mercator Projection
- Lambert Conformal Conic Projection
- Polar Azimuthal Projection
- Equal Area Projection
- Compromise Projection
🎯 Chapter 5 – Map Projection (20 Exam-Oriented MCQs)
1. A map projection is a method of:
A. Measuring land
B. Representing the Earth's curved surface on a flat surface
C. Calculating area
D. Drawing symbols
2. The main reason for using map projections is:
A. To reduce printing costs
B. To represent the curved Earth on a flat map
C. To increase map size
D. To improve paper quality
3. Which of the following is not a developable surface?
A. Cylinder
B. Cone
C. Plane
D. Sphere
4. Which projection is best suited for equatorial regions?
A. Cylindrical Projection
B. Conical Projection
C. Azimuthal Projection
D. Polyconic Projection
5. Which projection is most suitable for mapping mid-latitude countries?
A. Cylindrical
B. Conical
C. Azimuthal
D. Gnomonic
6. Which projection is commonly used for polar regions?
A. Cylindrical
B. Conical
C. Azimuthal
D. Mercator
7. The Mercator projection is a type of:
A. Conical Projection
B. Cylindrical Projection
C. Azimuthal Projection
D. Equal Area Projection
8. Which property is preserved in a conformal projection?
A. Area
B. Shape and local angles
C. Distance everywhere
D. Population
9. Which projection preserves area?
A. Equal Area Projection
B. Mercator Projection
C. Gnomonic Projection
D. Perspective Projection
10. In a cylindrical projection, distortion is greatest near the:
A. Equator
B. Standard Parallel
C. Poles
D. Centre
11. Meridians in a conical projection are:
A. Parallel straight lines
B. Curved lines
C. Straight lines converging at the apex
D. Circular arcs
12. Parallels in an azimuthal projection are generally:
A. Straight lines
B. Concentric circles
C. Parallel lines
D. Random curves
13. Which projection is commonly used for marine navigation?
A. Mercator Projection
B. Lambert Equal Area
C. Polar Azimuthal
D. Bonne Projection
14. Which property cannot be preserved simultaneously with all others in a single projection?
A. Shape
B. Area
C. Distance
D. All of the above
15. A projection that preserves true direction from a central point is:
A. Azimuthal Projection
B. Cylindrical Projection
C. Conical Projection
D. Polyconic Projection
16. Which projection is widely used for aviation charts?
A. Mercator
B. Lambert Conformal Conic
C. Robinson
D. Mollweide
17. Which field commonly uses map projections for georeferencing and spatial analysis?
A. Music
B. GIS
C. Literature
D. Accounting
18. Which of the following is an example of a compromise projection?
A. Robinson Projection
B. Mercator Projection
C. Lambert Conformal Conic
D. Polar Azimuthal
19. The choice of map projection mainly depends on:
A. Map colour
B. Paper size
C. Purpose and area to be mapped
D. Font style
20. Which statement is TRUE?
A. Every map projection is free from distortion.
B. One projection preserves shape, area, distance, and direction perfectly.
C. Every map projection introduces some distortion.
D. Map projections are unnecessary in GIS.
✅ Answer Key
| Q.No | Answer | Q.No | Answer |
|---|---|---|---|
| 1 | B | 11 | C |
| 2 | B | 12 | B |
| 3 | D | 13 | A |
| 4 | A | 14 | D |
| 5 | B | 15 | A |
| 6 | C | 16 | B |
| 7 | B | 17 | B |
| 8 | B | 18 | A |
| 9 | A | 19 | C |
| 10 | C | 20 | C |
🏆 Your Score
| Score | Performance |
|---|---|
| 18–20 | 🌟 Projection Expert |
| 15–17 | 🎯 Exam Ready |
| 10–14 | 👍 Good – Revise Once |
| Below 10 | 📚 Needs More Practice |
💡 Study Tips
- Memorise the three developable surfaces: Cylinder, Cone, and Plane.
-
Remember the best application of each projection:
- Cylindrical → Equatorial regions & navigation
- Conical → Mid-latitude regions
- Azimuthal → Polar regions
- Understand the difference between equal-area, conformal, equidistant, true-direction, and compromise projections.
- Practise drawing simple diagrams of cylindrical, conical, and azimuthal projections.
- Solve previous CTEVT questions on map projection properties and applications.
🎯 Lessons Learned
After studying this chapter, you should be able to:
✅ Define a map projection.
✅ Explain why map projections are necessary.
✅ Describe the three developable surfaces used in projections.
✅ Classify map projections based on developable surfaces and preserved properties.
✅ Compare cylindrical, conical, and azimuthal projections.
✅ Select an appropriate projection for different mapping purposes.
📖 Frequently Asked Viva Questions
- What is a map projection?
- Why is a map projection required?
- What is a developable surface?
- Name the three developable surfaces used in cartography.
- What is a cylindrical projection?
- Explain a conical projection.
- What is an azimuthal projection?
- What is the Mercator projection used for?
- Differentiate between equal-area and conformal projections.
- Why can't one map projection preserve shape, area, distance, and direction simultaneously?
- Which projection is suitable for Nepal and why?
- Which projection is best for marine navigation?
- Which projection is commonly used for polar mapping?
- What factors influence the choice of a map projection?
-
State the applications of map projections in GIS and surveying.
📘 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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