drawing cross section pp

Describing Landscape on Topographic Maps

Geography Module #2 Unit #2 Lesson #10

OBJECTIVESOBJECTIVES

What are contour lines/

What are contour lines/

Contour IntervalContour Interval

Cross Section Cross Section

Drawing Cross SectionsDrawing Cross Sections

QUIZQUIZ

INTRODUCTIONINTRODUCTION Slopes on Topographical Maps

Slopes on Topographical Maps

Landforms on Topographical Maps

Landforms on Topographical Maps

Objectives

As a result of this lesson, you will be able to 1) Define contour lines, relief, cross section 2)Calculate contour interval3)Distinguish between landforms with similar contour

patterns 4)Describe landforms through the reading of contours5)Describe entire landscape through reading of contours 6)Draw cross sections7)Recognize the importance of interpreting relief on

topographic maps

Introduction

Contour lines are used on topographical maps to show how the height and shape of land changes. They are also used to draw cross sections which give a side view of landforms. This presentation demonstrates how cross sections are drawn.

Contour patterns are also used to identify different landforms. This presentation will show you various contour patterns and the features they represent.

What are contour lines?

Contour lines are lines drawn on topographic maps joining places of equal height above sea level.

Contour lines

Contour Lines

On topographical maps contour lines are the brown lines with the values written in the gaps within the line.

Contour interval or vertical interval

Contour interval is the difference in height between one contour line and the next.The vertical interval for this map is 100 metres.

Cross Sections

Contour lines are used to draw cross sections. A cross section is a side view of an area or feature. Cross sections help us to visualize an area.

Drawing Cross Sections

Before you begin to draw a cross section imagine yourself walking or driving across the area. You can do this by reading the contours.

Watch the animation on the next slide

Animation – on next slide show person walking from B to A on contour map and on cross section.

Drawing Cross Sections

Drawing Cross Sections

Identify the two points between which you want to draw the cross section.Draw a line to connect the two points.

Drawing Cross Sections

Lay edge of plain sheet of paper along the line and mark starting point and end point.Mark and attach value to each contour line that touches the edge of the paper

Drawing Cross Sections

Plot points on a graph paper.Distance on horizontal axis and height on vertical axis.Join the dots to see the shape of the land

Drawing Cross Sections

Enclose the cross section.Shade the area.Label the cross section.Give it a title. Include the horizontal scale and vertical scale.

Slopes on a Topographical Map

A steep slope or a scarp slope is shown by contours that are close together.

Try to identify the steep slope on slide # 9

Steep slope

Slopes on a Topographical Map

A gentle slope or a dip slope is shown by contours that are far apart.

Try to identify the gentle slope on Slide # 9

Gentle slope

Landforms on Topographic Map

Conical Hill- contour pattern Conical Hill

Conical hill

Conical hills are so called because they are shaped like cones and taper to a point. The space within the innermost contour is small.

Round -topped Hill

Round -topped Hill

A round –topped hill is represented by concentric contour lines with increasing values toward the centre. The outer contours are not always circular. The space within the innermost contour is comparatively large.

Flat -topped Hill

Flat-topped Hill

The innermost (highest) contour line encloses a wide space. The contours are not usually circular.

Plateau

A plateau is a large highland area with an almost flat top.

Ridge

Long narrow strip of highland. Contours are elongated, almost parallel.

Valley

A valley is a lowland between two highlands. Contour lines point to higher land.

Gorge

A ravine is a very narrow steep-sided valley. The contours are very close together. A very deep ravine is called a gorge.

Subtopic 1 Activity

Matching activity Students will be required to match pictures of features to

contour patterns and contour patterns to descriptions. Students will be asked to drag and match five sets in 15

seconds.

Animation Example

End of Activity

You have reached the end of the activity. If you wish to review other concepts in this lesson, go to the first slide.If you have finished viewing the lesson, click the Close (X) button.

28