contour

1. Created by tbonnar.

3.  In real life we see in 3D, but maps are only two
dimensional. It is therefore difficult for maps to show
three dimensions.

4.  It is possible,
but very
difficult, to
create a form
of 3D map such
as those shown
here.

5.  There are two
ways maps try to
show 3D:
 1. Profile
(SideView)

7.  There are two ways
maps try to show
3D:
 2. Contour Map
(TopView)

9.  A Contour MapTakes a
3D representation and
turns it into a 2D map.

10.  Contour lines are a
map’s way of showing
you how high the land
is.
 They join together
places of the same
height and form
patterns that help us to
imagine what the land
actually looks like.

11.  Contour lines
are drawn in
intervals that
never change
and never
cross each
other.

12.  Contour maps are used in atlases, because they can
provide more detailed information about a location.
 For example, in the two boxes below we can predict
the shape of the land based on the contour line.

16.  We can also learn about the steepness of the
slope(in math class this would be called the
gradient). In the box below we can see that
the distance between the lines indicates the
slope.
gentle/
not steep
cliff – lines
are touching
steep

17.  The closer together the contour lines are, the steeper
the land. Contour lines that are wide apart show us that
the land is flatter.

18. Stop here to do Contour
Pages 1 & 2.

19.  Contour lines are created by first finding spot
heights (heights at particular places) for a
whole region and then connecting the
locations that have identical spot heights.

20.  Below, you can see two examples of
“connecting the dots” in order to create
contour lines.

21.  Note that the contour lines have different contour
intervals. Maps usually specify the contour interval.
 Usually the contour interval is a round number. Ex. 10
metres or 100 metres
 Try connecting the dots in the example below.

22.  Note that the contour lines have different contour
intervals. Maps usually specify the contour interval.
 Usually the contour interval is a round number. Ex. 10
metres or 100 metres
 Try connecting the dots in the example below.