Intervening Obstacles
• Hinders migration
• Historical- mountains deserts oceans
• Modern Day- passports, visas
U.S. Quota Laws
• 1924:
• 1965
• 1978
• 1990
• Preferences
– Family reunificaton (chain migration)
– Skilled workers
– diversity
• Brain Drain
Unauthorized immigration
• Characteristics of unauthorized immigrants
– Source country
– Children
– Years in the United States
– Labor Force
– Distribution
Undocumented Immigration to
the United States
• Undocumented
immigrants
– ½ enter legally (students,
tourists) but remain after
they are supposed to leave
– ½ illegally cross the border
without passport or visa
– Become “documented” with
forged documents
– The minority caught are
deported
• Americans divided on issue
of immigration
• 1986 Immigration Reform
and Control Act
– Could become permanent
residents if they could prove
continuous residence &
apply for citizenship after 5
years
– Few applied
– Discouraged immigration
• it made it harder for recent
immigrants to get jobs
because of employer fines
U.S. States as Immigrant Destinations
Fig. 3-8: California is the destination of about 25% of all U.S. immigrants; another
25% go to New York and New Jersey. Other important destinations
include Florida, Texas, and Illinois.
U.S. Immigrant Destinations
• ¼ California
• ¼ New York, Florida,Texas
• Coastal Cities
• Similar distribution whether legal or illegal
• Mexico  California, Texas, Illinois
• Caribbean New York, Florida
• Chinese, Indians California, New York
• Other Asians California
Undocumented Immigration:
Mexico to Arizona
Fig. 3-7: The complex route of one group of undocumented migrants from a small
village north of Mexico City to Phoenix, Arizona.
United States/Mexico Border
Characteristics of Migrants
• Gender• Age and Education
Immigration Concerns in the
United States
• Border Patrols
• Workplace
• Civil Rights
• Local Inititives
• Label controversy
– Unauthorized immigrant, undocumented
immigrant, illegal alien
Immigration Concerns in Europe
• Sources
• Opponents of Immigration
• Europeans as Emigrants
Undocumented Immigrants in the US
Fig. 3-7: California, Texas, and Florida are the leading destinations for
undocumented immigrants to the U.S.
U.S. Mexico
Border
at Tijuana
The U.S. side of the border
is uninhabited and
separated from Mexico by a
fence
U.S. States as Immigrant Destinations
Fig. 3-8: California is the destination of about 25% of all US immigrants; another
25% go to New York and New Jersey. Other important destinations
include Florida, Texas, and Illinois.
What are the “US gateway” states? Story of a migrant
http://www.pbs.org/pov/alotrolado/lesson_plan.php#activity
Guest Workers
Migrants allowed into a country to fill a labor need,
assuming the workers will go “home” once the
labor need subsides
 Have short term work visas
 Send remittances to home country
Guest
Workers in
Europe
Fig. 3-9: Guest workers emigrate mainly from Eastern Europe and North Africa to work in
the wealthier countries of Western Europe.
Global Remittances
http://www.economist.com/node/21553458/print
Turkish Kebab Stand in
Germany
Gravity Model
• When applied to migration, larger places
attract more migrants than do smaller
places.
• Destinations that are more distant have
weaker pull effect than do closer
opportunities of similar caliber
AP Human Geography
GRAVITY
MODEL
Gravity Model
• Uses size of location and
distance as factors for travel
• Size of location takes
precedent over distance
• The gravity model can be
used to estimate:
• Traffic Flows
• Migration between two areas
• The number of people likely
to use one central place
 The GRAVITY MODEL of
MIGRATION is a model, derived from
Newton's law of gravity.
 Newton's law states that: "Any two bodies
attract one another with a force that is
proportional to the product of their masses and
inversely proportional to the square of the
distance between them.”
 The GRAVITY MODEL of
MIGRATION is used to predict the
degree of interaction between two
places
When used geographically, the
words 'bodies' and 'masses' are
replaced by 'locations' and
'importance' respectively,.
Importance can be measured in
terms of population numbers,
gross domestic product, or other
appropriate variable.
 The gravity model of
migration is therefore based
upon the idea that as the
importance of one or both of
the location increases, there
will also be an increase in
movement between them.
o The farther apart the two
locations are, however, the
movement between them will
be less.
o This phenomenon is known
as distance decay.
The simplistic version of the gravity model of migration is as
follows:
Mij=
Pi*Pj
dij2
Mij = gravity model prediction of migration
between origin i and destination j
Pi = population of origin State i
Pj = population of destination State j
dij = distance from origin i to destination j
CITY
ATLANTA
NEW YORK CITY
KNOXVILLE
AUSTIN
LOS ANGELES
CHICAGO
TULSA
POPULATION (2012)
443,775
8,336,697
182,200
842,592
3,857,799
2,714,856
393,987
COMPARE ATLANTA TO EACH OF THE CITIES LISTED
Ullman’s Spatial Interaction
Model
AP Geography
Travel patterns for purchase of clothing and yard
goods. A) Canadian rural cash-economy.
B) Canadian older Mennonite sect.
Very different
travel behaviors
show the
differences that
may exist in the
“action spaces”
of different
cultural groups
occupying the
same territory.
Getis, Getis, Fellmann
Getis, Geits, Fellmann
Chicago Travel Patterns: shows 96% of all trips.
What factors influence & create these patterns of
interaction?
Edward Ullman’s Theory
• Spatial Interaction
is controlled by
three flowdetermining factors.
1. Complementarity
2. Transferability
3. Intervening
Opportunity
Complementarity
• For two places to
interact, one place must
have a supply of an item
for which there is an
effective demand.
• Example: product: Oil Interaction: US - Middle East
• Differences of place is
not enough to create
interaction.
• Example: rain forest and
Greenland
What is Effective Demand?
• Desire for the item
(demand)
• Purchasing Power - $$$
• Means to transport the
product - rail, road,
internet, ship etc.
Transferability
• Refers to mobility of
a commodity
• Spatial interaction
occurs only when
acceptable costs of
an exchange are
met.
• Costs include both
Time and Money
Transferability Function of Three
Conditions.
• Characteristics and value of product.
• The distance measured in time and money.
• The ability of the commodity to bear the
costs of movement.
– Both physical and economic.
– If the time and money costs are too great
interaction does not occur.
– Buyer seeks substitute or goes without product.
Intervening Opportunity
B
C
A
• Closer opportunities will
reduce the the
attractiveness of
interaction with more
distant- even slightly
better- alternatives.
• Example -ski area in Big
Bear. The snow is not as
good as Tahoe. But
people in Southern Calif.
are more likely to ski in
Big Bear.
Measuring Spatial Interactions
Key Concepts and Theories
Friction of Distance
• Distance has a retarding effect on human
interactions because there are increasing
penalties in time and cost associated with
longer distances.
Space-Time Compression
• How do we measure relative distance - miles,
time, cost?
• How is this different than absolute distance?
• What effects has information technology had on
relative distance?
• Discuss - impacts on daily lives, cultural change,
migration.
• Draw graphic to illustrate Space-Time
Compression
Refugees
People who flee across an international boundary because
of a well-founded fear of being persecuted for reasons of
race, religion, nationality, membership of a particular social
group, or political opinion
Refugees: Sources & Destinations
Fig. 3-1: Major source and destination areas of both international and internal refugees.
Hurricane Katrina Migrants
A major natural disaster represents an environmental push factor for forced
migration.
Scene from The Grapes of Wrath
The Dust Bowl in the 1930s led to forced migration from the Great Plains to California
and elsewhere.
Regions of Dislocation
• Subsaharan Africa
• North Africa and Southwest Asia
• South Asia
• Southeast Asia
• Europe
How Do Governments Affect
Migration?
• Immigration laws
• U.S. history
– Little restriction
– Quotas by
nationality
– Selective
immigration