Topographic Maps
- “Topography” means shape of the land
- A topographic map shows to scale:
- the width
- length
- variable height above a datum (reference
point, usually mean sea level)
- Basically they are a 2-D representation of a
3-D surface.
Topo Map Sample
Reading a Topo Map:
1. The Symbols:
Topo maps use a variety of symbols in
different colors to represent specific land
features (both man-made and natural)
Man-made
features
(buildings)
* You do not
have to write
these down,
you will get a
copy
2. The title
It is found in the top right hand corner
of the map & at the bottom right corner:
The next map is named in
each corner or side
Map Scales: Tells you how much surface
area is covered by map
Fractional Map Scale: i.e. 1:24,000 means
that 1 inch of map equals 24,000 inches on
Earth
Graphic (Bar) Scale: shows relationship
between map and distance on Earth like
miles or km ex. 1 inch = 20 miles
This graphic bar scale tells you how
much of map is equivalent to 1 mile
Latitude
- Lines of latitude are circular bands
running east and west parallel to the
equator.
- Lines of latitude are designated
from zero to 90 degrees north and
south of the Equator.
Longitude
- Lines of longitude are circular bands
which run north and south through the
two poles.
- Lines of longitude are designated from
zero to 180 degrees east and west of
the Greenwich Observatory in London,
England.
The 35°15'
number is the
latitude
The 111°30'
number is the
longitude Contour Lines on Topographic Maps
* Contour lines mark areas of equal
elevation
* Contour interval = difference in elevation
between lines
Rules:
1. Never branches or splits
2. Steep slopes = closely spaced contour lines
3. Never cross but can merge to show a cliff
Contour Line Rules cont...
4. Hills are pictured by concentric circles of
contour lines
5. Craters or depressions are marked with
closed circles with hatch marks
6. Contour lines that cross stream channels
form a “V” that points upstream
1. Label a
hill.
2. Write
“steep”
where it is
steepest.
3. What is
the contour
interval?