Important terminology of Maps

NCERT Class 11//Chapter 1 Introduction to The Maps

1. Cadastral Map

Meaning:
A cadastral map is a large-scale map showing individual land parcels and their legal/property boundaries. Each parcel is normally identified by a unique number or reference.

Key features:

Very large scale, commonly around 1:500 to 1:4000 in the definition you provided.
Shows individual plots, field boundaries, roads, buildings and other property-related details.
Parcel numbers help identify land records.
Primarily concerned with land ownership, taxation and administration.
High positional detail is required.

Example: A village land-record map showing the boundaries and plot numbers of individual farms.

Exam point:
Cadastral map → land parcels + boundaries + parcel identification.

Important: Cadastral-map scales are not universally fixed. They vary according to country, surveying practice and purpose.

2. Cardinal Points

The four cardinal directions are:

Cardinal Point	Symbol	Direction
North	N	0° / 360°
East	E	90°
South	S	180°
West	W	270°

They provide the fundamental framework for orientation and direction on maps.

Intermediate directions

Between cardinal points are the intercardinal directions:

NE — Northeast
SE — Southeast
SW — Southwest
NW — Northwest

Exam point:
Cardinal points are directions, not physical features.

3. Cartography

Cartography is the discipline concerned with the creation, design, production, analysis, interpretation and use of maps.

It combines:

Art → visual design and communication
Science → geographical measurement and principles
Technology → GIS, remote sensing, digital mapping and computer-based techniques

Modern cartography includes:

Data collection → processing → generalisation → symbolisation → map design → production → interpretation

Major branches

Topographic cartography
Thematic cartography
Digital cartography
Statistical cartography
Web cartography

Exam point:
Cartography is broader than map-making alone; it includes the study and effective use of maps.

4. Map Generalisation

Map generalisation is the process of selecting, simplifying and modifying geographical information when preparing a map at a smaller scale.

Why is it necessary?

Suppose a detailed map of a city contains thousands of buildings. If the same area is represented on a small-scale national map, showing every building would make the map overcrowded and unreadable.

Therefore, cartographers may:

Select important features
Omit less important features
Simplify shapes
Aggregate nearby features
Displace features slightly to improve readability
Exaggerate very small but important features

Example

A detailed road network on a 1:10,000 map may be reduced and simplified on a 1:1,000,000 map.

Important principle:
As scale becomes smaller → generalisation generally increases.

5. Geoid

The geoid is an irregular, equipotential surface that approximately corresponds to mean sea level extended beneath the continents.

Your supplied definition calls it an oblate spheroid, but this should be corrected for precise geography.

Geoid ≠ Ellipsoid

Geoid

Irregular surface
Related to Earth's gravity field
Approximates mean sea level
Used as a reference for elevations/heights

Ellipsoid

Mathematical, smooth and regular surface
Approximates Earth's overall shape
Used extensively in geodesy, GPS and coordinate systems

Important exam distinction

Geoid → physical/gravity-based reference surface
Ellipsoid → mathematical reference surface

The Earth is approximately an oblate spheroid/ellipsoid, not a perfect sphere.

6. Map

A map is a selective, symbolic and generalised representation of all or part of the Earth's surface, or another geographical phenomenon, on a reduced scale.

Three words in the definition are especially important:

① Selective

Not every real-world object is shown.

② Symbolised

Real-world features are represented through conventional symbols, colours, lines and patterns.

③ Generalised

Features are simplified according to the purpose and scale of the map.

Essential elements of a map

Usually include:

Title
Scale
Direction/north arrow
Legend/key
Symbols
Coordinate/grid system
Source
Projection, where relevant

Exam formula:

Map = Selection + Symbolisation + Generalisation + Scale

7. Map Series

A map series is a systematic collection of maps covering different areas but produced according to common specifications, such as scale, sheet layout, projection, symbols and design.

Characteristics

Same or standardised scale
Consistent cartographic conventions
Common projection/specifications
Adjacent sheets fit together
Covers a large territory systematically

Example

A national topographic mapping programme may divide a country into numerous sheets. Each sheet represents a particular area, but all sheets follow the same mapping standards.

Map sheet vs Map series

Map sheet → one individual map
Map series → a coordinated collection of related map sheets

8. Map Projection

A map projection is a systematic mathematical method of representing the Earth's curved surface on a flat map.

Because the Earth is approximately spherical/ellipsoidal and a map is flat, some distortion is unavoidable.

Main types according to developable surface

1. Cylindrical

Mercator
Transverse Mercator

2. Conical

Lambert Conformal Conic
Albers Equal-Area Conic

3. Azimuthal/Planar

Polar stereographic
Lambert Azimuthal Equal-Area

What can be distorted?

A projection may distort:

Area
Shape
Distance
Direction

Therefore, no single projection preserves everything perfectly over the whole globe.

Exam point:
Projection = mathematical transformation from curved Earth to a plane.

9. Scale

Scale expresses the relationship between a distance on a map and the corresponding distance on the ground.

Representative Fraction

If:

Scale = 1 : 50,000

then:

1 unit on map = 50,000 of the same units on ground.

For example:

1 cm on map = 50,000 cm on ground = 500 m = 0.5 km

Three common forms of scale

1. Statement scale
1 cm represents 1 km.

2. Representative Fraction (RF)
1 : 100,000

3. Graphic/Bar scale
A line divided into ground-distance intervals.

Large vs small scale

Large-scale map	Small-scale map
More detail	Less detail
Smaller area	Larger area
Less generalisation	More generalisation
Example: cadastral map	Example: world map

Important:
A large-scale map does NOT mean a large geographical area. It means a larger amount of detail per unit area.

10. Sketch Map

A sketch map is a simplified, usually freehand representation of an area that focuses on important locations and spatial relationships rather than precise measurement.

Characteristics

Usually not drawn to exact scale
May not preserve true orientation
Simplified
Emphasises important landmarks
Useful for explaining routes and locations
Does not require surveying-level accuracy

Example

A student drawing a rough route:

Home → School → Market → Railway Station

The exact distances may not be correct, but the relative arrangement is communicated.

🔥 Most Important Comparisons

Cadastral Map vs Sketch Map

Cadastral	Sketch
Precise	Approximate
Large scale	Usually not to scale
Property-focused	Location/route-focused
Parcel boundaries	General features
Parcel numbers	Usually no parcel numbers

Map vs Map Projection

Map = final graphical representation.
Projection = mathematical method used to transform Earth's curved surface for mapping.

Geoid vs Ellipsoid

Geoid: irregular gravity-based reference surface.
Ellipsoid: smooth mathematical approximation of Earth.

Scale vs Generalisation

Scale determines the level of detail that can practically be represented.
As scale becomes smaller, generalisation becomes more important.

🧠 High-Yield Concept Chain

Earth's curved surface
↓
Geoid / Ellipsoid reference surface
↓
Map Projection
↓
Scale selection
↓
Generalisation
↓
Symbolisation & Cartographic design
↓
Final Map