Chapter 1 covers the fundamentals of topographic map reading, detailing its key components such as grid lines, scales, and the representation of physical and human features. It explains how to determine grid references with examples, the methods for measuring straight and curved distances, and describes directions using compass points and bearings. Additionally, it highlights contour lines for elevation, river features, drainage patterns, and calculating gradients, ultimately presenting techniques for interpreting and creating cross-sections of relief features.

1. Chapter 1
Map
Reading

2. What is a topographic map ?
• Large-scale map representing selected aspects of the
earth’s surface
• Shows both physical and human features
Components of a topographic map
• Title
• Grid lines
• Names of places
• Scale
• Direction
• Contours
• Legend and symbols
Chapter 1: Map Reading

3. Chapter 1: Map Reading
Some basic components of a topographic map
Title
Place
name
Grid lines
Scale
Contour Symbols

4. Grid lines
• Eastings – vertical lines that run from south to north
• Northings – horizontal lines that run from west to east
• Grid lines are numbered to provide the coordinates of
specific features on a map
Grid reference
• Set of digits formed using the grid values of eastings
and northings
• Defines a location on a map
• The more digits in a grid reference, the more precise
the location, e.g. a six-figure grid reference gives a
more accurate location than a four-figure grid reference
Chapter 1: Map Reading

5. Four-figure grid reference
• Identifies a specific grid square
• First two digits = Value of the easting on the left of the
square
• Second two digits = Value of the northing at the bottom
of the square
32
31
30
65 66 67
X
Example:
The four-figure grid
reference for Point X is
6530.
Chapter 1: Map Reading

6. Six-figure grid reference
• Identifies a specific point in a grid square
• How:
1. Determine the four-figure grid
reference
2. Divide the space between the two
eastings of the grid square into ten
equal intervals
3. Count how many tenths the point is
from the left to right – add this
number after the first two digits of the
four-figure grid reference
4. Repeat Step 2 for the northings of the
grid square
5. Count how many tenths the point is
from the bottom up – add this number
to the end of the grid reference
Example:
The six-figure grid
reference for Point
X is 655305
X
32
31
30
65 66 67
Chapter 1: Map Reading

7. Scale
• Shows what a certain distance on the map represents
on the land in the real world
• Three ways to indicate scale on a map:
1. Line scale
– E.g.
2. Word statement
– E.g. “1cm on the map equals 30km on the ground”
3. Representative fraction
– E.g. ‘1:50,000’ means that one unit on the map represents
50,000 units on the ground in the real world
4
0 2 km
Chapter 1: Map Reading

8. 1. Place a strip of paper on the
line between the two points
2. Mark the two points on the
edge of the paper strip
3. Place the marked edge of the
paper strip on the line scale
4. Read the distance between
the two points
Reading the straight-line distance between two points
Chapter 1: Map Reading

9. 1. Place one end of a string at one end of the path to be
measured (point ‘C’)
2. Using the string, trace the curved path
3. Mark the end of the path on the string (point ‘D’)
4. Place the string on the line scale
5. Read the distance off the scale
Reading the length of a curved path
Chapter 1: Map Reading

10. Direction
• Two ways to describe the direction of a place
1. Using compass points
– Cardinal points of the compass: north, south, east, west
– Intercardinal points: northeast, southeast, southwest,
northwest
2. Using bearings
– Direction of a place is
expressed as an angle (in
degrees) clockwise from
the base direction (0)
– Base direction could be
grid north, magnetic north
or true north
Chapter 1: Map Reading

11. Grid north
• Direction of the vertical grid lines (called eastings) on a
map
Magnetic north
• Direction of the magnetic
north pole
True north
• Direction of the geographic
north pole
Chapter 1: Map Reading

12. Land elevation
1. Contours
– Lines on the map joining places with the same height
– The number on a contour line indicates the height that the line
represents
2. Spot heights
– Points on the map showing
the heights of hills
100
200
998
Chapter 1: Map Reading

13. 3. Benchmarks
– Marked points of known elevation which serve as reference
points from which the height of other places may be established
4. Trigonometrical stations
– Points marked by metal discs mounted on stable foundations
such as concrete pillars
– Usually located on top of mountains or hills
– May be used as benchmarks for measuring elevation
4.38
480
Chapter 1: Map Reading

14. Recognising relief features
• The shape of contour lines and the spacing between
them show us the shape, height and slope of relief
features
Chapter 1: Map Reading
A plateau A mountain Undulating relief

15. Chapter 1: Map Reading
A gentle slope A stepped slope A steep slope

16. River features
• Topographic maps can give us some information on the
river features of an area
1. River source
– Point where a river originates
2. River mouth
– Point where a river ends
3. River course
– Path followed by a river
– Perennial course flows throughout the year
– Indefinite or seasonal course flows only during certain
seasons
4. Watershed
– Boundary between two drainage basins
Chapter 1: Map Reading

17. 5. Drainage pattern
– Pattern formed by the rivers in a particular drainage basin
Chapter 1: Map Reading
Trellis pattern
Dendritic pattern
Centripetal pattern Radial pattern

18. Cross-sections
• Drawing cross-sections will help you identify relief
features
• How:
1. Draw a line (XY) across the map where the cross-section is to
be drawn.
Chapter 1: Map Reading

19. 2. Place a strip of paper on the
line XY. Moving from left to
right, mark each point on the
edge of the paper where XY
meets a contour.
Chapter 1: Map Reading
3. On another piece of paper,
draw the horizontal and
vertical axes for the cross-
section. The horizontal axis
should be the length of XY.
Choose a suitable scale for
the vertical axis.

20. 4. Place the marked edge of the
paper strip (from Step 2) along
the horizontal axis of the cross-
section graph. For each mark
on the paper strip, draw a
vertical line up to the equivalent
height and mark off with a dot.
Chapter 1: Map Reading
5. Join all the dots with a
smooth curve to complete
the cross-section of XY.

21. Gradient
• Tells us how steep a slope is
• To calculate gradient:
Vertical distance
Gradient =
Horizontal distance
• A gradient of 1:25 means that for every horizontal
distance of 25 units covered, you would ascend one
unit
Chapter 1: Map Reading