Physical Geology Interactive: The Lab - Maps (Activities-Activity 3)

Activity 3: Contour Profiles and Vertical Exaggeration

Although a contour map

shows how a variable changes

with spatial position, it is sometimes

difficult to visualize the

change in

the vertical dimension.

To depict changes in the

magnitude of a variable along a

particular direction in the map area,

it is useful

to make a plot of

that variable on the

vertical axis versus position

on the horizontal axis (Fig. 1).

Contour profiles or cross sections

are planes oriented

perpendicular to a map that

show how the variable

changes in the direction

perpendicular to the plane of the map.

They can be used to show

the vertical character of the

Earth's surface (topographic profiles),

the top of the water table

(water table profile),

the depth of the ocean floor (bathymetry profile),

or any other contoured variable.

By plotting the contoured quantity

on the vertical axis versus

the

horizontal distance, profiles

show the difference in the

variable along the profile and

how fast that parameter changes

with horizontal distance.

Fig. 1: Topographic profile showing the elevation of the Earth's surface.

Contour profiles can be drawn

following a simple set of rules.

To illustrate the

nature of the

surface cut by the profile,

it is sometimes necessary to construct a

profile with different

horizontal and vertical scales.

This produces

vertical exaggeration of the

surface trace and should be

indicated on the diagram.

To complete Activity 3, select one of the following files: