Topographic Map Notes:
A topographic map is a two-dimensional (flat) representation of a portion of
the three-dimensional (3D) surface of the earth.
Topographic maps use lines called contour lines, to show the details of
Earth’s surface. It shows all the different elevations, how rugged or smooth
the land is valleys, ravines, cliffs, hills, mountains, gently sloping land and
water features in the area.
Contour Lines: Contour lines are used to determine elevations and are lines on a
map that are produced from connecting points of equal elevation (elevation refers to
height in feet, or meters, above sea level).
The following are general characteristics of contour lines:
1. Contour lines do not cross each other, divide or split.
2. Closely spaced contour lines represent steep slopes, conversely, contour lines that are
spaced far apart represent gentle slopes.
3. Contour lines trend up valleys and form a "V" or a "U" shape. This could be where
the contour lines are showing a stream, river or some other type of valley or ravine.
Index Contour lines: On most topographic maps, index contour lines are generally
darker and are marked with their elevations.
Intermediate Contour lines: are the lighter colored contour lines found in
between each index contour line. They move up in specific intervals set by the map key.
Supplementary
Lines: These contour lines
resemble dashes. They show
changes in elevation of at
least one-half the contour
interval. These lines are
normally found where there
is very little change in
elevation, such as on fairly
level terrain.
To show a depression (dip) within an elevation, you will see an area with dashed lines drawn
inward like shown in the area below:
ex.
Topographic maps give us details that profile pictures cannot:
ex.
Topographic maps will come with detailed keys and legends and scales needed for that area:
Legend ex:
Vertical Scale or Contour Interval: this tells you how many feet or meters are
between each contour line, so you may know correct elevations of the land.
Scale ex:
HAPPY MAPPING!