LESSON 11 
MappiInGc CONTOURS 
HE purpose of this lesson is to teach the mean- 
ing and use of contour lines on maps. The 
pupil must be able to read contours at a glance, 
and he should be able to draw them correctly 
upon his own maps. 
Definition 
A contour is a line upon a plan or map connecting points of 
equal elevation. The shore line of a body of standing water is a 
true contour. 
Since every part of a contour line is of the same elevation the 
ground on one side of a contour is always higher and on the other 
side always lower than the contour. All the elevations between 
any two contours must be higher than one and lower than the other. 
Contours are not necessarily parallel, as the ground surface is 
very irregular. On steep slopes they are near together, on nearly 
Jevel land they are far apart and often vary greatly in direction. 
A contour can never cross the shore of a body of standing water. 
A contour may cross the shore of running water but it can cross the 
same shore once only and will then appear on the farther shore at 
a point nearly opposite. 
Contour lines are rarely made up of straight portions joined by 
relatively sharp angles: they are usually of a series of tangent curves, 
especially in cleared and cultivated land. At the abrupt edges of 
artificial cuts or fills or of naturally eroded banks they do have rather 
sharp angles. 
Contours cannot cross each other, except in the very unusual 
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