Objectives

1
Objectives
Types of Maps

• Compare and contrast different map projections.

• Analyze topographic maps.
• Describe map characteristics, such as map scales
  and map legends

Vocabulary

• Mercator projection
• conic projection
• gnomonic projection
• topographic map

• contour line
• contour interval
• map legend
• map scale

2
Types of Maps
Types of Maps

• Maps are flat models of a three-dimensional
  object, Earth.

• All flat maps distort to some degree either the
  shapes or the areas of landmasses.
• Cartographers use projections to make maps.
• A map projection is made by transferring points
  and lines on a globes surface onto a sheet of
  paper.

3
Mercator Projections
Types of Maps

• A Mercator projection is a map that has parallel
  lines of latitude and longitude.

• In a Mercator projection, the shapes of the
  landmasses are correct, but their areas are
  distorted.

4
Conic Projections
Types of Maps

• A conic projection is a map made by projecting
  points and lines from a globe onto a cone.

• The cone touches the globe at a particular line
  of latitude along which there is very little
  distortion in the areas or shapes of landmasses.
• Distortion is evident near the top and bottom of
  the projection.

5
Gnomonic Projections
Types of Maps

• A gnomonic projection is a map made by projecting
  points and lines from a globe onto a piece of
  paper that touches the globe at a single point.

• Gnomonic projections distort direction and
  distance between landmasses.
• Gnomonic projections are useful in plotting
  long-distance trips by air or sea.

6
Gnomonic Projections
Types of Maps

• Great circles are imaginary lines that divide
  Earth into two equal halves.

• On a sphere such as Earth, the shortest distance
  between two points lies along a great circle.
• Navigators connect points on gnomonic
  projections to plot great-circle routes.

7
Topographic Maps
Types of Maps

• Topographic maps are detailed maps showing the
  elevations of hills and valleys of an area.

• Topographic maps use lines, symbols, and colors
  to represent changes in elevation and features
  on Earths surface.

8
Topographic Maps
Types of Maps

• Contour Lines

• Elevation on a topographic map is represented by
  a contour line.
• A contour line connects points of equal
  elevation.

• Elevation refers to the distance of a location
  above or below sea level.

9
Topographic Maps
Types of Maps

• Contour Intervals

• Topographic maps use contour lines to show
  changes in elevation.
• The contour interval is the difference in
  elevation between two side-by-side contour
  lines.

• The contour interval is dependent on the
  terrain.

10
Topographic Maps
Types of Maps

• Index Contours

• Index contours are contour lines that are marked
  by numbers representing their elevations.
• If a contour interval on a map is 5 m, you can
  determine the elevations represented by other
  lines around the index contour by adding or
  subtracting 5 m from the elevation indicated on
  the index contour.

11
Topographic Maps
Types of Maps

• Depression Contour Lines

• Depression contour lines are used to represent
  features that are lower than the surrounding
  area.
• On a map, depression contour lines have
  hachures, or short lines at right angles to the
  contour line that point toward the lower
  elevation, to indicate depressions.

12
Map Legends
Types of Maps

• Topographic maps and most other maps include both
  human-made and natural features that are located
  on Earths surface.

• These features are represented by different
  symbols.
• A map legend explains what the symbols represent.

13
Map Scales
Types of Maps

• When using a map, you need to know how to measure
  distances.

• A map scale is the ratio between distances on a
  map and actual distances on the surface of Earth.

14
Map Scales
Types of Maps

• There are three types of map scales verbal
  scales, graphic scales, and fractional scales.

• A verbal scale expresses distance as a statement,
  such as One centimeter is equal to one
  kilometer.
• A graphic scale consists of a line that
  represents a certain distance, such as 5 km or 5
  miles.
• A fractional scale expresses distance as a ratio,
  such as 163 500.

15
Section Assessment
Types of Maps

• 1. Match the following terms with their
  definitions.
• ___ projection
• ___ contour interval
• ___ map legend
• ___ map scale

A. the difference in elevation between two
side-by-side contour lines B. a diagram that
explains what the symbols on a map
represent C. a map made by transferring points
and lines on a globes surface onto a sheet of
paper D. the ratio between distances on a map and
actual distances on the surface of Earth
C A D B
16
Section Assessment
Types of Maps

• 2. Which type of map would be best suited for the
  following applications?
• ___ An aviator is trying to identify the
  shortest route between New York and London.
• ___ A cartographer for the state department
  of transportation has been tasked with making a
  new state road map.
• ___ A group of friends is planning on hiking
  in the back country of Idaho.
• ___ A sailor is sailing up the coast from
  South America to North America.

A. Mercator projection B. conic
projection C. gnomonic projection D. topographic
C B D A
17
Section Assessment
Types of Maps

• 3. What does it mean if a map says Scale 1100
  000?

This fractional scale means that one unit on the
map represents 100 000 units on Earths surface.
For example, one inch on the map would equal 100
000 inches on Earths surface.
18
End of Section 2