1. Earth’s Topography

2. Although our planet is called Earth, much of it is covered with water
All the land on Earth is surrounded by oceans
How much of the Earth’s surface is covered with water?
25%
50%
70%
90%

3. Way to go! You’re on your way to becoming a topography wiz
Click the image to continue

4. Major Land Divisions All the land on Earth can be categorized as
being one of the following:
Landmasses
Continents
Islands

5. Landmasses
Landmasses are areas of land consisting of one or more continents
There are only four major landmasses
Asia, Africa and Europe
North, South and Central America
Antarctica
Australia

6. Continents
Continents are landmasses that measure millions of square kilometers and rise a considerable distance above sea level
There are seven continents
Africa
Antarctica
Asia
Australia
Europe
South America
North America

7. Islands
Islands are small landmasses which are completely surrounded by water
Which of the following continents is also an island?
Africa Australia South America

8. Way to go! You know your continents
Click the image to continue

9. Sorry, your answer was incorrect
Click the image to go back and try again

10. Topography Topography refers to the shape of the Earth’s surface
The surface of the Earth is changed by
Weather conditions
Running water
Earthquakes and volcanoes
People

11. Earth’s topography is made up of different kinds of landscapes
Landscapes are the physical features of the Earth’s surface
Landscapes are defined by their
Elevation- Height above sea level
Relief- The difference in a region’s elevation
There are three main types of landscape regions
Mountains
Plains
Plateaus

12. North
American
Landforms

13. Mountains Natural landforms that reach high elevations
Rise at least 600 meters above the surrounding land
Have narrow summits, steep slopes, and high relief

14. Shaping Mountains
Mountains result from the folding and breaking of Earth’s surface due to movements of portions of the crust
Can be created when hot magma from within the Earth breaks through the surface
Streams and rivers often carve valleys in mountains

15. Groups of Mountains
Mountain range- A roughly parallel series of mountains that have the same general shape and structure
Mountain system- A group of mountain ranges in an area
Mountain belt- A large group of mountains which includes mountain ranges and mountain systems

16. Plains
Plains are flat areas that have very small differences in elevation
Areas of low relief
Characterized by broad rivers and streams

17. Coastal Plains
Coastal plains are low, flat areas located along a coast
Formed when soil and silt were deposited on the edge of a continent
The fertile soil makes farming a major activity

18. Interior Plains
Interior plains are low flat areas found inland on a continent
Elevations are higher above sea level than coastal plains
Sediments deposited by rivers and streams make the soil good for farming

19. Plateaus
Plateaus are broad, flat areas of land that rise more than 600 meters above sea level
Surfaces are fairly flat
Have low relief
Most plateaus are located inland
Often have the same landscape for thousands of kilometers
Many plateaus of the world are dry, nearly desert like

20. Introduction to Maps
Map- A drawing of the Earth, or part of the Earth, on a flat surface
Globe- A spherical, or round, model of the Earth
The most accurate
representation of the entire surface of the Earth
Shows the shapes, sizes, and locations of all the Earth’s landmasses
and bodies of water

21. Map Scales Both maps and globes are drawn to scale
The scale compares distances on a map or globe to actual distances on the earth’s surface
The more closely the map approaches the land in size, the larger the scale will be

22. Ways to show scale on a map
Verbal
Fractional
Graphic

23. Parallels
Parallels are lines going from east to west across a map or globe
Imaginary lines that
completely circle the Earth
Cross meridians at right
angles
Used to measure latitude

24. Latitude Latitude- Measure of distance north and south of the equator
Lines are numbered in degrees from 0° at the equator to 90° at the poles
Latitudes must be labeled as
being either north or south
of the equator
One degree of latitude is equal
to approximately 69 land miles

25. Meridians
Meridians- Lines that run between the geographic North and South poles of the Earth
Each meridian represents half of an imaginary circle around the Earth
Prime Meridian- The meridian
running through Greenwich,
England (0° longitude)
Used to measure longitude

26. Longitude
Longitude- Measure of distance east and west of the prime meridian
Lines are numbered in degrees from 0° at the prime meridian to 180° at the international date line
Longitudes must be designated as being either east or west of the prime meridian
Unlike lines of latitude, meridians
are not parallel (farthest apart at
the equator and get closer as they
near the poles)

27. Time Zones
Time zone- A longitudinal belt on the Earth in which all areas have the same local time
The Earth has been divided into 24 time zones that are 15° wide
Why 15° wide?
360° (deg. in a circle)
24 (hrs in a day)
There are 4 time zones in
the contiguous United
States (eastern, central,
mountain, & pacific)
= 15° (movement per hour)

28. Determining Local Time
When you cross from one time
zone to another, the local time
changes by one hour
Traveling east- you add one
hour for each time zone
you cross
Traveling west- you subtract
one hour for each time zone

29. Crossing the International Date Line
The international date line is a special meridian (180° E or 180° W)
Not only do you change the time when you cross it, you also change the day
Traveling east- add one hour, but subtract a day
Traveling west- subtract one hour,
but add a day

30. Maps Maps show locations and distances
Since the Earth is not flat, all maps have some distortion
Causes changes in the shapes and sizes of landmasses and
oceans
The smaller the
area mapped,
the less distortion

31. Projecting Our Globe Onto A Flat Surface
Globes are the most accurate way to represent the surface of the Earth
Since it’s not practical to carry a globe into the field, map makers must figure out how to represent a round map on a flat piece of paper

32. Mercator or Cylindrical Map Projections
A Mercator or cylindrical projection map is the most common type of map that we see
It’s like projecting an image of the globe on a movie screen that’s been wrapped around it
Areas close to the equator
have very little distortion
The closer to the poles that
one travels the more distorted
the map becomes
Used for navigation

33. Conic Projections
A conic projection map is created by placing a cone shaped screen on a globe
Produces a fairly accurate representation of the portion of the Earth’s surface being mapped
Used for making
topographic maps

34. Gnomonic or Plane Projection
A gnomonic or plane projection is created by placing an imaginary screen directly above, or below a globe
Used to plot the shortest distance between two points
Since it distorts both direction
and distance, this type of map
projection is seldom used

35. Interrupted Projection
There are many different types of interrupted
projection maps
Depict the continents as accurately as possible by leaving blank space in the less important areas of the map, such as in the oceans

36. Equal-Area Projection
For equal-area projections the meridians and parallels are placed on the map so that every part of the Earth is the same size on the map as it is on the globe
Correctly shows the
amount of area a
landmass covers,
but distorts its shape

37. Topographical Maps
Topographic maps show the different shapes and sizes of land surfaces
Show small details of the topography of an area
Shows the location of landscape and cultural features
Show the relief, or elevation change, of the land

38. Contour Lines
Most topographic maps use contour lines to show the relief of the land
Contour line- A line that passes through points on a map that have the same elevation (height above sea level)
Index contour- A bolder/wider brown line that has the elevation value marked at various intervals as a part of the line
These contours typically occur
every fifth line
Use an index contour near the point
for which you are trying to find the
elevation as a first step to determining
the elevation of that point

39. Contour Interval
Contour interval- The difference in elevation from one contour line to the next
The size of the interval depends on the relief of the land (mountains will need a bigger interval than a plain)
To calculate the contour interval, determine the distance between two successive index contours and then divide that number by 5
Step 1: ft – 700 ft = 100 ft
Step 2: ft ÷ 5 = 20 ft
The contour interval would be 20 ft

40. Rules for using contour lines
Contour lines never cross or intersect
Closely spaced lines represent a steep slope
Contours spaced far apart represent a gentle slope
Contour lines that cross a valley are V-shaped
Contour lines form V’s that point upstream, or in a direction opposite the flow of the stream
Contours form closed loops around hilltops or depressions
Short dashes called hachures are used to indicate a depression
All contour lines either close or extend to the edge of a map

41. Mapping Etiquette
To make reading and using a map easier, all maps should have a:
Title- to know what you’re looking at
Compass rose or north facing arrow- to determine direction
Map scale- to determine distance
Map key (or legend)- to explain symbols used
Way to determine the contour interval on topographic maps

42. Bel Isle

43. A First Look at Spectacle Island

44. Reading A Topographic Map
Spectacle Island
Contour interval = 3 meters
Elevation of the shoreline = ?
Elevation of the north drumlin = ?
Elevation of the visitor center = ?
Elevation of the highest point = ?
How deep is the ocean off the
southwest tip of the island ?