1. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Copyright © 2013 John Wiley & Sons, Inc. All rights reserved.

2. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Places Are Connected Through Human Interaction
Ideas
Information
Money
Products
People
What other types of spatial interactions can you suggest?
© 2013 John Wiley & Sons, Inc. All rights reserved.

3. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Migration: A permanent change in one’s place of residence to outside one’s community of origin
Occurs at various spatial scales:
Rural to urban
Urban to urban
Global
Figure 4.1
At what scale might you migrate in the future?
At what scale have you migrated in the past?
Why would China want to control internal migration within their own country?
© 2013 John Wiley & Sons, Inc. All rights reserved.

4. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Factors of Place Desirability
Less desirable places
More desirable places
What are some of the “more-desirable places” to migrate to within your state, province, or country?
What are some of the “less-desirable places” to migrate to within your state, province, or country?
© 2013 John Wiley & Sons, Inc. All rights reserved.

5. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Immigration:
Migration across an international border
What would you give up if you needed to send money to support your family in another country?
© 2013 John Wiley & Sons, Inc. All rights reserved.

6. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Birthplace for foreign born population shows
Historical immigration trends
Figure 4.2
How did U.S. immigration laws favor northwestern Europeans and exclude people from other regions in the world?
© 2013 John Wiley & Sons, Inc. All rights reserved.

7. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Illegal Immigrant Jumps Border Fence into Nogales, Arizona
Figure 4.3
What would you do if you were desperate to provide for your family and there were no jobs in your home country?
What should be the U.S. policy towards Mexican migrants?
© 2013 John Wiley & Sons, Inc. All rights reserved.

8. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Refugees Immigrate Due to Persecution in Their Home Country
Pull Factors
Push Factors
Better employment
More pleasant environment
Near to family
Affordable housing
Desirable climate
High housing costs
Rising crime rates
Traffic gridlock
High taxes
Poor climate
Undesirable employment
What are some other migration push and pull factors?
How might an issue be both a push and a pull factor (i.e., some want to be close to family, others want to get away from family)?
© 2013 John Wiley & Sons, Inc. All rights reserved.

9. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Migrant Selectivity
Figure 4.4
After age, what is the second most important migrant selectivity factor?
What role does length of residence play in migrant selectivity?
© 2013 John Wiley & Sons, Inc. All rights reserved.

10. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Distance Decay
Figure 4.5
How has the friction of distance changed since a century ago? Why?
What other types of interactions (besides migration) decay with distance?
© 2013 John Wiley & Sons, Inc. All rights reserved.

11. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Migration Streams
Figure 4.6
How do Dust Bowl-Era migration streams continue to impact the United States today?
© 2013 John Wiley & Sons, Inc. All rights reserved.

12. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Ten Largest Domestic Migration Streams of Persons Born in Mexico
Ten Largest Domestic Migration Streams of Persons Born in Cuba
Migration Streams and Counter Streams
Figure 4.7
What states/cities see substantial migration back and forth among Cubans? Why?
What states/cities see substantial migration back and forth among Mexicans? Why?
Based on these maps, where is the net population of Cubans and Mexicans increasing?
© 2013 John Wiley & Sons, Inc. All rights reserved.

13. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Ten Largest Domestic Migration Streams of Persons Born in Mexico
Ten Largest Domestic Migration Streams of Persons Born in Cuba
Gravity Model
What happens to the predicted interaction when a given variable increases or decreases?
What types of applications might the gravity model have for planners? Businesses?
Can the model perfectly predict migration?
© 2013 John Wiley & Sons, Inc. All rights reserved.

14. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Migration to California
Figure 4.8
How does this map reflect the gravity model’s ability to predict migration to California?
© 2013 John Wiley & Sons, Inc. All rights reserved.

15. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Mobility
Part of the American experience
Is high in developed countries with immigrant background
Past migration is an indicator of future migration
How is migration reflected as part of the American experience in popular culture such as movies?
What other countries besides the U.S. and Canada have high mobility patterns?
© 2013 John Wiley & Sons, Inc. All rights reserved.

16. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Moving to a new home is common in the United States
Figure 4.9
How many in your class have moved?
© 2013 John Wiley & Sons, Inc. All rights reserved.

17. Chapter 4: Newton’s First Law of Migration: The Gravity Model
US Mobility Rates
Figure 4.10
Why do you think annual mobility rates have changed over time?
© 2013 John Wiley & Sons, Inc. All rights reserved.

18. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Largest Interstate Migration Streams
Figure 4.11
Why are there strong interstate migration streams between some regions and weak ones between others?
© 2013 John Wiley & Sons, Inc. All rights reserved.

19. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Net Migration Rates by State
Figure 4.12
Why are there differences in mobility in different countries / states / provinces / cities?
© 2013 John Wiley & Sons, Inc. All rights reserved.

20. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Regional and Subregional Shifts in Population
Net Migration
Migration Patterns Reflect:
Location of states
Historical patterns of movement
Changing economic geography
Perceptions about place
How does migration impact population distribution within your country in terms of mobility? Cultural regions?
How are historical patterns and perceptions about places reflected in today's migration?
© 2013 John Wiley & Sons, Inc. All rights reserved.

21. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Name That Key Term
© 2013 John Wiley & Sons, Inc. All rights reserved.

22. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Movements of ideas, information, money, products, and people between places.
A permanent change in residence to outside one’s community of origin.
A move across international borders.
A person who is outside his or her country due to a well-founded fear of persecution and who is unable or unwilling to return.
A well-defined migration channel from a specific origin to a particular destination.
Spatial Interaction Migration Immigration Refugee Migration Stream
© 2013 John Wiley & Sons, Inc. All rights reserved.

23. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Migration that runs opposite to a migration stream. The tendency for certain types of people to migrate. Age, education, and other sociodemographic characteristics are ________ ________ factors. The percentage gain or loss of population due to migration. It is calculated as in-migrants minus out-migrants divided by the total population, all times 100. Positive numbers indicate net gain; negative numbers indicate net loss. Reasons to move from a particular place. Reasons to move to a particular place.
Migration Counterstream
Migration Selectivity
Net Migration Rate
Push Factors
Pull Factors
© 2013 John Wiley & Sons, Inc. All rights reserved.

24. Chapter 4: Newton’s First Law of Migration: The Gravity Model
A scatter of dots showing the relationship between two variables. Each dot on the graph represents the x and y coordinates of a different observation or case. A model to predict spatial interaction, where size (population) is directly related to interaction and distance is inversely related to interaction. A point on a scatter diagram that is roughly in line with the main trend but is separated from the main group of points because of its very high or low value. Money sent by immigrants from host country to home country.
Scatter Diagram Gravity Model Extreme Value Remittances
© 2013 John Wiley & Sons, Inc. All rights reserved.

25. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Point on a scatter diagram that lies far off the trend line. ________ on the graph correspond to cases that are poorly predicted by the model. ________ are not to be confused with extreme values, which may lie far from any other point but which are still close to the best-fitting line. The difference between an actual observed value of some variable and its predicted value using the gravity model. The declining intensity of an activity with increasing distance from its point of origin.
Outlier
Residuals
Distance Decay
© 2013 John Wiley & Sons, Inc. All rights reserved.

26. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Case Study
Activities
© 2013 John Wiley & Sons, Inc. All rights reserved.

27. Chapter 4: Newton’s First Law of Migration: The Gravity Model
After completing this chapter, you will be able to:
Apply principles of spatial interaction to patterns of movement.
Identify the major source areas for migration to your state.
Use functions of a spreadsheet.
Produce and interpret a scatter diagram.
Discriminate between positive and negative residuals.
Identify outliers on a scatter diagram.
Think critically about models in human geography.
© 2013 John Wiley & Sons, Inc. All rights reserved.

28. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Activity 1: Predicting Migration
with the Gravity Model
© 2013 John Wiley & Sons, Inc. All rights reserved.

29. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Activity 1: Predicting Migration with the Gravity Model
© 2013 John Wiley & Sons, Inc. All rights reserved.

30. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Activity 1: Predicting Migration with the Gravity Model
© 2013 John Wiley & Sons, Inc. All rights reserved.

31. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Activity 2: Scatter Diagram
© 2013 John Wiley & Sons, Inc. All rights reserved.

32. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Figure 4.13
© 2013 John Wiley & Sons, Inc. All rights reserved.

33. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Extreme values to delete and outliers to label
Cluster of points expands when extreme values are deleted
© 2013 John Wiley & Sons, Inc. All rights reserved.

34. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Activity 3: Residual Map
© 2013 John Wiley & Sons, Inc. All rights reserved.

35. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Canadian Examples
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36. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Canadian Examples
© 2013 John Wiley & Sons, Inc. All rights reserved.

37. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Activity 2: Scatter Diagram
© 2013 John Wiley & Sons, Inc. All rights reserved.

38. Chapter 4: Newton’s First Law of Migration: The Gravity Model
Activity 3: Residual Map
© 2013 John Wiley & Sons, Inc. All rights reserved.