Lesson Note on Methods Of Representing Relief: Contours, Hill Shading and Spot Heights for SSS 2

Class: Senior Secondary School 2 (SS2 / SSS 2)
Term: 3rd Term
Week: 3
Age: 16 years
Duration: 45 minutes
Subject: Geography
Curriculum Theme: Physical Geography
Previous Lesson: Representation Of Relief Forms: Conventional Signs and Physical Features.
Topic: Methods of representing Relief
Subject Matter: Contour representation, hill shading, relief colouring, spot heights, hachures, bench marks, boundary pillars, trigonometrical stations, choosing appropriate method to show relief on maps

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

• Identify different methods of representing relief on maps.
• Explain each method of relief representation.
• State the features shown by each method.

Affective Domain:

• Appreciate the importance of relief representation in map reading.
• Value the accuracy of different relief representation methods.

Psychomotor Domain:

• Identify examples of each relief representation method on map samples.
• Suggest appropriate methods for representing specific relief features.

Social Domain:

• Participate actively in class discussions about relief representation.

Reference Materials

The following resources were used in planning this lesson:

• 9 Years Basic Education Curriculum (Senior Secondary Geography)
• State Unified Scheme of Work (Geography SS2)
• Areola, O., & Leong, S. (2001). Certificate Physical and Human Geography for Senior Secondary Schools. University Press PLC.
• https://www.studyadda.com/notes/methods-of-representing-relief-features-on-maps/6789
• https://www.geography.learnontheinternet.co.uk/topics/reliefrepresentation.html

Instructional Materials

The teacher will teach this lesson with the aid of:

• Topographical maps
• Atlas
• Sketches and diagram samples of various relief representations
• Rulers
• Drawing paper

Rationale for the Lesson

This lesson is important because it helps pupils understand how the shape and height of land are shown on maps. Learning these methods enables pupils to interpret geographical information accurately, which is useful for various purposes like planning, construction, and understanding environmental processes.

Prerequisite/Previous Knowledge

Pupils have some basic knowledge of maps, their components, and general features of the land surface.

Lesson Content/Board Summary

Methods of Representing Relief on Maps

1. Contour Representation

Contour lines are imaginary lines drawn on a map connecting points of the same height above sea level. They are the most accurate method for showing relief.

The following are properties of contour lines:

• Closely spaced contours indicate a steep slope.
• Widely spaced contours indicate a gentle slope.
• Uniformly spaced contours indicate a uniform slope.
• Contour lines never cross each other.
• They form V-shapes pointing upstream when crossing a river, indicating a valley.
• They form U-shapes pointing away from higher ground, indicating a spur.
• Concentric circles of increasing height indicate a hill or mountain.

2. Hill Shading

Hill shading is a method where relief is shown by varying the intensity of shading on a map. Areas that would be in shadow if illuminated from a particular direction (usually the northwest) are shaded darker, while sunlit areas are left lighter or unshaded.

This method gives a visual impression of the three-dimensional shape of the land.

3. Relief Colouring (Layer Tinting)

Relief colouring, also known as layer tinting, uses different colours to represent varying heights of land above sea level. Each colour band represents a specific range of elevation.

Common colour schemes include:

• Green for lowlands (e.g., 0-200m)
• Yellow or light brown for middle elevations (e.g., 200-500m)
• Darker brown for highlands (e.g., 500m and above)
• Blue for water bodies and white for permanent snow/ice.

4. Spot Heights

Spot heights are exact elevations of specific points on the land surface, usually marked with a dot and a numerical value (e.g., •250) on a map. They represent the precise height of a particular location, such as a hill summit, road junction, or a specific point of interest.

Spot heights provide precise elevation data for individual points.

5. Hachures

Hachures are short, broken lines drawn on a map to indicate the direction and steepness of a slope. They run in the direction of the steepest gradient.

The following are characteristics of hachures:

• Thicker and shorter hachures indicate steeper slopes.
• Thinner and longer hachures indicate gentler slopes.
• They point downhill, showing the direction water would flow.
• They do not provide specific elevation values.

6. Bench Marks (BM)

Bench marks are permanent survey points marked on solid objects like rocks, walls, or bridges, indicating their exact height above sea level. They are often denoted by “BM” followed by the height value on maps.

Bench marks serve as reference points for surveying and construction.

7. Boundary Pillars (BP)

Boundary pillars are physical markers placed on the ground to indicate administrative or property boundaries. On maps, they are represented by specific symbols and often labelled “BP”.

They help in defining and identifying limits of areas.

8. Trigonometrical Stations (Trig. Station)

Trigonometrical stations are prominent points on high ground, such as hilltops, whose exact positions and heights have been determined by triangulation surveys. They are represented by a triangle symbol (Δ) with a numerical value indicating their height.

Trigonometrical stations are important control points for mapping and surveying.

Choosing Appropriate Methods to Show Relief on Maps

The choice of method depends on the purpose of the map, its scale, and the level of detail required.

Factors to consider include:

• Purpose: A map for hiking might need detailed contours, while a general reference map might use relief colouring.
• Scale: Large-scale maps can show more detail with contours; small-scale maps might rely on hill shading or relief colouring for broader representation.
• Accuracy: Contours and spot heights provide precise elevation data, while hachures and hill shading give a visual impression without exact values.
• Clarity: Overlapping methods can make a map cluttered, so a balance is often sought.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher introduces the lesson by asking pupils how they think mountains, valleys, and plains are shown on maps. The teacher explains that maps represent a 3D world in 2D, and various methods are used to show the vertical dimension (relief).
Pupils’ Activity: Pupils respond to the questions and share their ideas about how landforms are represented on maps.
Learning Point: Pupils are introduced to the concept of relief representation on maps.

Step 2: Contour Representation

Time: 7 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains what contour lines are, their properties (e.g., spacing for steepness, V-shapes for valleys), and how they are used to depict relief. The teacher shows examples of contour lines on topographical maps and diagrams.
Pupils’ Activity: Pupils observe the map samples, listen to the explanation, and ask questions for clarification.
Learning Point: Pupils understand contour lines and their use in showing relief.

Step 3: Hill Shading and Relief Colouring

Time: 7 minutes
Teaching Skill: Explanation/Visualisation
Teacher’s Activity: The teacher explains hill shading and relief colouring. For hill shading, the teacher demonstrates how light and shadow create an illusion of relief. For relief colouring, the teacher shows an atlas or map with different colours representing different altitudes and explains the colour scheme.
Pupils’ Activity: Pupils examine the provided maps and diagrams, noting the effects of shading and colour on relief perception.
Learning Point: Pupils learn about hill shading and relief colouring as methods of showing relief.

Step 4: Spot Heights and Hachures

Time: 7 minutes
Teaching Skill: Explanation/Identification
Teacher’s Activity: The teacher defines spot heights and hachures. The teacher shows examples of spot height markings and hachure lines on map samples, explaining what each indicates about the land surface.
Pupils’ Activity: Pupils identify spot heights and hachures on the maps and understand their specific uses.
Learning Point: Pupils understand spot heights and hachures and their role in relief representation.

Step 5: Bench Marks, Boundary Pillars, Trigonometrical Stations

Time: 7 minutes
Teaching Skill: Explanation/Identification
Teacher’s Activity: The teacher explains what bench marks, boundary pillars, and trigonometrical stations are, their symbols, and their significance as relief indicators or reference points on maps. The teacher points out examples on topographical maps.
Pupils’ Activity: Pupils identify these specific features on the maps and understand their importance.
Learning Point: Pupils learn about bench marks, boundary pillars, and trigonometrical stations.

Step 6: Choosing Appropriate Methods

Time: 5 minutes
Teaching Skill: Discussion/Critical Thinking
Teacher’s Activity: The teacher leads a discussion on factors influencing the choice of relief representation method, such as map purpose, scale, and desired level of detail. The teacher asks pupils to suggest which method would be best for different scenarios (e.g., showing a hiking trail vs. a general overview of a country).
Pupils’ Activity: Pupils participate in the discussion, offering suggestions and justifying their choices.
Learning Point: Pupils learn to consider factors when choosing an appropriate method to show relief.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define contour lines.
2. Mention three methods of representing relief on maps.
3. Explain the difference between hill shading and relief colouring.
4. State one characteristic of hachures.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key methods of relief representation discussed and reiterates their importance in map interpretation. The teacher assigns homework, asking pupils to find a map and identify at least two different relief representation methods.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their understanding of the lesson.

Lesson Keywords

• Contour – An imaginary line on a map connecting points of equal elevation above sea level.
• Hill shading – A method of representing relief by using shadows to give a three-dimensional effect.
• Relief colouring – Using different colours to indicate varying ranges of elevation on a map.
• Spot height – An exact elevation of a specific point on the ground, marked with a dot and value.
• Hachures – Short, broken lines indicating the direction and steepness of a slope.
• Bench mark – A permanent survey mark indicating a precise elevation, usually on a fixed object.
• Trigonometrical station – A point on high ground whose exact position and height are determined by surveying.

Differentiation

For pupils who grasp concepts quickly, the teacher will encourage them to research advanced methods of relief representation or analyze complex topographical maps. For pupils needing more support, the teacher will provide simplified diagrams and offer one-on-one guidance during activity sessions, focusing on identifying basic representations.

Note for teachers using this lesson plan

Teachers should adapt this lesson plan to suit the specific needs and context of their pupils. Utilize local examples of relief features where possible to make the lesson more relevant. Ensure sufficient visual aids are available for effective demonstration of each relief representation method.