contours on os maps
DESCRIPTION
By the end of the lesson students should be able to: -explain how height is shown on maps -recognise slope types -some will identify landscape features from looking at contoursTRANSCRIPT
Lesson objectives:
Knowledge:
All will explain how height is shown on maps
Most will recognise slope types
Some will identify landscape features from looking at contours
Skills:
All will will complete the contour shading task.
Most will be able to plot the cross section of a route
Some will shade your cross section & add landscape features
Keywords for today's lesson:
Contours
Gradient
Slope
Elevation
Topographic
Intervals
They are these type of lines on a map
What are contours?
The lines connect areas of equal altitude on a map
Why do we use contours?
True or False
1. Maps are Flat
2. Hills are not Flat
Contours lines are the easiest way of showing changes in height of the landscape on a map
Why do we use contours?
• They can be used to learn about the shape of the land (the relief).
• A map with only a few contour lines will be flat (and often low lying)
• If a map has lots of contours it is a mountainous or hilly area.
Contours lines are the easiest way of showing changes in height of the landscape on a map
Remember that the closer together the contour lines the steeper the slope.
Gentle slopes
Steep slopes
X Y
200
250
225
225
200
200
250
275300275250
225
225
200
250250
200
300
225
200
225
275
So, how do they work?
100125150175200225250275
300
200
250
225
225
200
200
250
275300275250
225
225
So, how do they work?
So, what do they look like on a map?
Convex slope
Concave slope
Steep slope
Gentle slope
Types of Slopes:
Where is the steepest slope on this island?
50
100
150
200
Steepest slope – contour lines are closest together
Slieve Dowdican 227
. 76
50
100
150
200
Sometimes spot heights can be shown as a dot with a note of the height of that place.
You can spot other features by the shape and pattern of the contours
A valley may look like this…
Often with a river running down through the valley
150
120
90
However, a spur can look very similar !
But here the heights are increasing in the opposite direction – always double check which way the contours are increasing or decreasing.
90
120
150
Valley Spur
90
120
15090
120
150
10
20 30
40
10 20 30
40
Valley
Spur
Key words
• Contour
• Elevation
• Topographic
• Intervals
A joined up line on a map showing the shape and height of the ground.
The height gained or lost in Meters on a map.
A type of map using large detail usually including contours.
The difference in elevation of contour lines
Activity
- Using the map, you are going to shade in areas of equal height (altitude) using the connecting contour lines
- You will use a key to show the heights shown
You need:-Your map-Colouring Pencils-Scrap Paper
Key
0-10 m
10-20m
20-30m
30-40m
40-50m
50-60m
What you need to do
1. Complete shading task on contour map2. Plot a cross section between X and Y on the
back of your sheet3. Add the shading to your cross section4. Mark on the two rivers
Have we met our lesson objectives?
Knowledge:
All will explain what are contours on a map
Most will explain why contours are important
Some will identify landscape features from looking at contours
Skills:
All will complete the contour shading task.
Most will be able to plot the cross section of a route
Some will shade your cross section & add landscape features