1.

Introduction to Maps
Essential Question: What information is presented in different types
of maps, and how do those maps show spatial patterns, the power of
geographic data, and relationships among places?

Geographers emphasize spatial patterns, which are the general arrangements

of things being studied and the repeated sequences of events, or processes,
that create them. Learning to recognize and use geographical patterns is a
fundamental skill in understanding the discipline. One of the most important
tools of geographers are maps. Improvements in geospatial and computer
technologies have dramatically increased the quality of maps, the accuracy of
data, and the variety of maps available to study and use. Maps and geospatial
data now influence everyday life with the use of smartphones and apps that
allow us to not only view maps but interact, modify, and show our own location
within the map.

Maps
Maps are the most important tool of a geographer and help to organize complex
information. No tool communicates spatial information more effectively than a
map. Maps are essential in highlighting and analyzing patterns. There are two
broad categories of maps: reference maps and thematic maps:

Reference Maps
Reference maps are aptly named because they are designed for people to refer
to for general information about places.
• Political maps show and label human-created boundaries and
designations, such as countries, states, cities, and capitals.
• Physical maps show and label natural features, such as mountains, rivers,
and deserts.
• Road maps show and label highways, streets, and alleys.
• Plat maps show and label property lines and details of land ownership.

1.1: Introduction to maps 9

 REFERENCE MAP OF MEXICO

UNITED STATES

Ciudad
Juárez

Gulf of
Mexico
MEXICO
PACIFIC
OCEAN CUBA
Guadalajara Ecatepec
Mexico City
Puebla
Inte
r-A
mer
ican
BELIZE
Hig
hw
ay

National capital
Highway
Major city GUATEMALA
Mountains
0 100 200 300 Kilometers
0 100 200 300 Miles

Reference map of Mexico from 2020. What type of reference material is included in the map? For what
purpose might this map be useful?

Thematic Maps
Thematic maps show spatial aspects of information or of a phenomenon.
Following are descriptions of four common types of thematic maps.
Choropleth maps use
various colors, shades of one
MAP
MAPPATTERNS
PATTERNS
color, or patterns to show the
location and distribution of
spatial data. They often show
rates or other quantitative data
in defined areas, such as the
percentage of people who speak
English.
Dot distribution maps are
Choropleth Graduated Symbol
used to show the specific location
and distribution of something
across a map. Each dot represents
a specified quantity. One dot
might stand for one school
building or for millions of people
who own dogs. While these maps
are known as dot distribution
maps, any kind of symbol—a Dot Distribution Isoline
triangle, the outline of a house, a
cow—can be used instead of dots.
10 HUMAN GEOGRAPHY: AP ® EDITION
 Graduated symbol maps use symbols of different sizes to indicate different
amounts of something. Larger sizes indicate more of something, and smaller
sizes indicate less. These maps make it easy to see where the largest and smallest
of some phenomena are by simply comparing the symbols to each other. The
map key is used to determine the exact amount. The symbols themselves are
arranged on the map centered over the location represented by the data, so
they may overlap. Graduated symbol maps are also called proportional symbol
maps.
Isoline maps, also called isometric maps, use lines that connect points
of equal value to depict variations in the data across space. Where lines are
close together, the map depicts rapid change, and where the lines are farther
apart, the phenomenon is relatively the same. The most common type of isoline
maps are topographic maps, which are popular among hikers. Points of equal
elevation are connected on these maps, creating contours that depict surface
features. Other examples of isoline maps are weather maps showing changes in
barometric pressure, temperature, or precipitation across space.
In a cartogram, the sizes of countries (or states, counties, or other areal
units) are shown according to some specific statistic. In the example below,
the cartogram of world population shows Canada and Morocco as roughly the
same size because they have similar populations (about 35 million people),
even though Canada is more than 20 times larger in area. Any variable for
which there are statistics can be substituted for the size of the country and
mapped in the same way. Cartograms are useful because they allow for data to
be compared, much like a graph, and distance and distribution are also visible,
like on a traditional map.

Canada China
United
States

Morocco
India

Indonesia

The size of each country reflects the total population. Based on the graphic, which countries have the
largest populations?

1.1: Introduction to maps 11

Scale
Nearly every map is a smaller version of a larger portion of the earth’s surface.
In other words, a map is a reduction of the actual land area it represents. Scale
is the ratio between the size of things in the real world and the size of those
same things on the map. A map has three types of scale: cartographic scale,
geographic scale and the scale of the data represented on the map. (See Topic
1.6 for more about scale.)
Cartographic scale refers to the way the map communicates the ratio of its
size to the size of what it represents:
• Words: for example, “1 inch equals 10 miles.” In this case, 2 inches on the
map would be 20 miles on the surface of the Earth.
• A ratio: for example, 1/200,000 or 1:200,000. This means that 1 unit of
measurement on the map is equal to 200,000 of the same unit in reality.
For example, 1 inch on the map represents 200,000 inches (or 3.15 miles)
on the ground.
• A line: for example, the map may show a line and indicate that its distance
on the map represents ten miles in reality. This is sometimes called a
linear, or graphic, scale.
• Scale: Small-scale maps show a larger amount of area with less detail—
global scale Earth at night is an example. Large-scale maps show a
smaller amount of area with a greater amount of detail—North America
at night is an example.
Types of Spatial Patterns Represented on a Map
Spatial patterns refer to the general arrangement of phenomena on a map.
Spatial patterns can be described in a variety of way utilizing important
geographic tools and concepts including location, direction, distance, elevation,
or distribution pattern.
Location
Locations may be absolute or relative. Absolute location is the precise spot
where something is according to a system. The most widely used system is the
global grid of lines known as latitude and longitude. Latitude is the distance
north or south of the equator, an imaginary line that circles the globe exactly
halfway between the North and South Poles. The equator is designated as 0
degrees and the poles as 90 degrees north and 90 degrees south.
Longitude is the distance east or west of the prime meridian, an imaginary
line that runs from pole to pole through Greenwich, England. It is designated
as 0 degrees. On the opposite side of the globe from the prime meridian is
180 degrees longitude. The International Date Line roughly follows this line
but makes deviations to accommodate international boundaries. Thus, on this
system, the absolute location of Mexico City is 19 degrees north latitude and 99
degrees west longitude.

12 HUMAN GEOGRAPHY: AP ® EDITION

 THE GLOBAL
THE GLOBAL GRID
GRID
150˚ 120˚ 90˚ 60˚ 30˚ 0˚ 30˚ 60˚ 90˚ 120˚ 150˚

ARCTIC OCEAN

60˚ 60˚

NORTH EUROPE
PACIFIC AMERICA ASIA
30˚ 30˚
OCEAN ATLANTIC PACIFIC
Mexico City
OCEAN AFRICA OCEAN
19˚N, 99˚W
0˚ Equator 0˚

SOUTH INDIAN

Prime meridian
AMERICA OCEAN

30˚
AUSTRALIA 30˚

0 2,000 Miles
0 2,000 Kilometers
60˚ SOUTHERN OCEAN 60˚

ANTARCTICA
150˚ 120˚ 90˚ 60˚ 30˚ 0˚ 30˚ 60˚ 90˚ 120˚ 150˚

Relative location is a description of where something is in relation to

other things. To describe Salt Lake City, Utah, as being “just south of the Great
Salt Lake and just west of the Rocky Mountains, on Interstate 15 about halfway
between Las Vegas, Nevada, and Butte, Montana,” is one way (of many) to
describe its relative location. Relative location is often described in terms of
connectivity, how well two locations are tied together by roads or other links,
and accessibility, how quickly and easily people in one location can interact
with people in another location.
Direction is used in order to describe where things are in relation to each
other. Cardinal directions such as north, east, south, or west or intermediate
directions such as southeast or southwest are commonly used to describe
direction. On most maps, north will be the top of the map, but be sure to look
on the map for cardinal direction clues.

THE RELATIVE LOCATION OF SALT LAKE CITY

CANADA
WASHINGTON

Butte MONTANA
OREGON
15

IDAHO
T E R S T ATE

WYOMING
NEVADA
CA

Salt Lake
LIF

City
OR

IN

Las
Vegas
NI

UTAH
A

This map shows the

ARIZONA relative location of Salt
Lake City along Interstate
0 500 Miles 15. What are advantages
0 500 Kilometers for business or cities being
MEXICO located near an interstate?

1.1: Introduction to maps 13

 Relative locations can change over time and as accessibility changes. For
example, the many ghost towns (abandoned settlements) of the western United
States once had relative locations near water sources (which dried up), along
trade routes (which changed), or near mines (which closed). Their good relative
locations lost the advantages of access to resources or trade that they once had.
However, their absolute locations, as described by the global grid of latitude
and longitude, remain the same.

Distance
Distance is a measurement of how far or how near things are to one another.
Absolute distance is usually measured in terms of feet, miles, meters or
kilometers. For example, the absolute distance from home to your school is
2.2 miles.
The term relative distance indicates the degree of nearness based on time
or money and is often dependent on the mode of travel. For example, traveling
from home to your school takes 10 minutes by car or 25 minutes walking.

Elevation
Elevation is the distance of features above sea level, usually measured in
feet or meters. The elevation of the summit of Mount Everest is over 29,000
feet. Elevation can impact a variety of things including climate, weather, and
agriculture. Usually, the higher the elevation, the cooler the temperature gets
and at very high elevations, it becomes more difficult for certain crops to grow.
Elevation is usually shown on maps with contours (isolines).

10
20
30
30
40
40
50
A B

50 50
40 40
30 30
20 20
10 10
0 0
A B

Source: usgs.gov
A contour map (isoline), like the one above, shows elevation of physical features.

14 HUMAN GEOGRAPHY: AP ® EDITION

Pattern Distribution
Geographers are also interested in distribution, the way a phenomenon is spread
out over an area (L2). Essentially, distribution is a description of the pattern of
where specific phenomenon are located. Geographers look for patterns, or the
general arrangement of things, in the distribution of phenomena across space
that give clues about causes or effects of the distribution. Common distribution
patterns include the following:
• Clustered or agglomerated phenomena are arranged in a group or
concentrated area such as restaurants in a food court at a mall or the
clustering of cities along the border of the United States and Mexico.
• Linear phenomena are arranged in a straight line, such as the distribution
of towns along a railroad line.
• Dispersed phenomena are spread out over a large area, such as the
distribution of large malls in a city.
• Circular phenomena are equally spaced from a central point, forming
a circle, such as the distribution of the homes of people who shop at a
particular store.
• Geometric phenomena are in a regular arrangement, such as the squares
or blocks formed by roads in the Midwest.
• Random phenomena appear to have no order to their position, such as
the distribution of pet owners in a city.

Projections
Because the earth is a sphere and maps are flat, all maps distort some aspect
of reality. The process of showing a curved surface on a flat surface is done
using a map projection. Cartographers decide whether they want to preserve
area, shape, distance, or direction on their map accurately, knowing that other
elements will have to be less accurate as the earth is “flattened” on their map.
Essentially all maps are distorted, but cartographers use different maps for
different purposes.
The Mercator, one of the most famous projections, was designed for
navigation because the lines of directions are straight and easy to follow. A
weakness of the Mercator on a global scale is that it makes the land masses
appear larger than reality as you move north or south from the equator. This
results in the countries of North America and Europe appearing larger and
possibly more powerful than the countries near the equator. Greenland’s size
on a Mercator looks to be the same size of Africa, however, in reality, Africa is
14 times the size of Greenland.
Geographers are concerned by the political and economic bias of power,
wealth, and superiority that can be subconsciously reinforced by using an
incorrect projection. All projections and maps have strengths and weaknesses.
The key is to understand this and select the best projection for the map.

1.1: Introduction to maps 15

 90º N 90º N

60º N 60º N

30º N 30º N
180º W

120º W

180º W

120º W
120º E

180º E

120º E

180º E
60º W

60º W
60º E

60º E
0º 0º

0º

0º
30º S 30º S

60º S 60º S

90º S 90º S

Mercator Projection Peters Projection

90º N
90º N 60º N 30º N 0º
30º S 45º S 60º N
180º W 180º E

30º N

180º W

120º W

120º E

180º E
0º

60º W

60º E
0º
120º W 120º E
30º S

60º S

60º W 60º E 90º S

0º

Conic Projection Robinson Projection

COMPARING MAP PROJECTIONS

Projection Purpose Strengths Distortion
(Weaknesses)
Mercator Navigation • Directions are shown • Distance between
accurately lines of longitude
• Lines of latitude and appears constant
longitude meet at • Land masses near the
right angles poles appear large
Peters Spatial distributions • Sizes of land masses • Shapes are
related to area are accurate inaccurate, especially
near the poles
Conic General use in • Lines of longitude • Direction is not
midlatitude countries converge constant
• Lines of latitude are • On a world map,
curved longitude lines
• Size and shape are converge at only one
both close to reality pole

Robinson General use • No major distortion • Area, shape, size,

• Oval shape appears and direction are all
more like a globe than slightly distorted
does a rectangle

16 HUMAN GEOGRAPHY: AP ® EDITION

REFLECT ON THE ESSENTIAL QUESTION

Essential Question: What information is presented in different types of maps, and

how do those maps show spatial patterns, the power of geographic data, and rela-
tionships among places?

Types of Maps Types of Information Ways to Describe

in Maps Spatial Patterns

KEY TERMS

physical geography physical maps International Date Line

human geography road maps relative location
Four-Level Analysis plat maps connectivity
analyze thematic maps accessibility
theory choropleth maps direction
concepts dot distribution maps patterns
processes graduated symbol maps absolute distance
models isoline maps relative distance
spatial models topographic maps elevation
nonspatial models cartogram distribution
time-distance decay scale clustered (agglomerated)
spatial patterns cartographic scale distribution
networks small-scale maps linear distribution
quantitative data large-scale maps dispersed distribution
geospatial data absolute location circular distribution
qualitative sources latitude geometric distribution
scales of analysis equator random distribution
reference maps longitude
political maps prime meridian

1.1: Introduction to maps 17