Module 4 Flashcards
Can be illustrated in two important ways:
} Distance of contacts from an origin
} Frequency of contacts at a particular distance from the origin
Propensity for Interaction
Cartographic portrayals of the consequences of interaction propensities
Flow Maps
Movement is ____?
Purposive
____ made on the basis of preferences and prejudices
Prejudgments
_____ result in patterns of place avoidance and place preference
Personal Images of Reality
_____ is most conveniently accomplished with a map
Space Searching
} Subjective image that is an integral part of our consciousness
} Information is not standardized
} No conventional signs or symbols
} Scale is highly distorted
Mental Maps
Psychological representations of places
Cognitive Images
The Real World -> _____ -> _____ -> ______ ->______?
- Information (Senses)
- Perception (Brain and Personality)
- Cognition (Culture)
- Recall (Transformed Cognitive Image)
} Known land/known world
} ____ affect the accuracy of knowledge
Terra Cognita, Distance Decay
- Status of cartography degenerated
- Latitudes, longitudes, astronomical measurements and projections were
forgotten
Roman Era
§ Theological considerations influenced space perception
§ Holy Land occupied and enormous area, paradise is located at the top of the map
Middle Ages
_____ are often not portrayed cartographically
Subjective Image
Studied individual’s perceptions of geographic space
Peter Gould
_____ made by individuals are related to the differential
evaluations they place upon various portions of their potential action space
Locational Decisions
} Subjective image are often not portrayed cartographically
} Peter Gould: Studied individual’s perceptions of geographic space
§ Locational decisions made by individuals are related to the differential
evaluations they place upon various portions of their potential action space
} Preferred area is the home region itself
} Steady decline in perceived desirability
} New Mexico gets an unusually low ratings in contrast to its neighboring states
} Implications for workers/immigrants
Nations and Regions
} Image of the city (Kevin Lynch)
} Well-travelled paths contribute to the formation of city images
} Some areas are deemphasized or ignored
} Not all city streets are perceived as paths even though they are usable for city travel
The City
} Area which contains the majority of destinations of a particular individual
} Subspace within the mental map
} Frequently tends to be discontinuous
Action Space
Determinants of the dimensions of Action Space:
Locational pattern of potential destinations
Time constraints
Cost Constraints
Regardless of the dimension of the action space, intensity of contacts ____ with distance from the home base
Decrease
§ Two individuals belonging to the same socioeconomic rank but to two contrasting
cultural groups may be expected to have interaction propensities
§ Differences in location of contacts and action spaces
Cultural Variations in Action Spaces
§ Opted for the nearest available source for low order convenience activities
§ Highly selective in their choice of destinations for high-order services
§ interaction propensities are not always motivated by the desire to minimize
distance or the cost of overcoming it
French Canadians and English Canadians
} Study of movement patterns of the individual at the metropolitan, nation and world
level is a physical impossibility
} Adequate generalizations cannot result from the study of the travel behavior of
specific individuals
} Preferred approach is to search for regularities in human behavior
Empirical Regularities in the Propensity for Interaction
Action Space and the Role of Distance:
- Distance Decay Functions
- Tobler’s First Law / Distance Decay:
- Everything is related to everything else, but near things are more related than
distant things.
- Everything is related to everything else, but near things are more related than
} Can be compared to a field around a magnet
} Reach of a magnetic field is a direct function of the power of the magnet
} Individual contact fields are also direct functions of their force or gravitational pull
Action Space
} Single individuals are molecules
} Groups are aggregates of molecules
} Behavior of any particular individual particle may be unpredictable
Social Physics
} Physical behavior is subject to random disturbances
} Occurrence of an event can only be predicted in probabilistic terms
} Considering large aggregates greatly diminishes the possibility of errors
Browmian Motion
} Human beings are considered in groups
} Unlike molecules, humans are decision-making units who are not subject to natural
forces in the same manner that physical matter is
} Modal individual
Macrogeography
} Sociological masses exert gravitational force
} Force declines with increasing distance between the masses
} Mass is considered to be greater than the sum of its parts
Social Physics
} Developing nations
} Cost factor play a significant role in less developed countries
} Locational system reflects the most important mode of movement
} Short distance movement
} Aggregate distance movement
Behavioral Departures
} Most widely used deterministic model
} Used to predict the degree of interaction between places
} Derived from Newton’s Law of Gravity
} The distance between two points and the size of their populations (mass) provide a
high level of statistical explanation for the volumes of flows.
} Population stands as a surrogate measure for demand and subsumes the impact of
many other factors.
} An adequate point of departure in modeling spatial flows is an adaptation to human
phenomena of ____ in physics of form
The Gravity Model
} We are surrounded by bodies of various sizes, and some of these are provided with
satellites, each having its local center of attraction, by means of which its parts are
held together
} ____ were treated as centers of absorption, and volumes of migratory
movement were shown to decrease with increasing distance between a given origin
and destination.
Carey (1858, 42-43) Principles of Social Science, Destinations
} Points out that the first attempt to use Carey’s concept in an operational context was
in a study of migration flows between English cities (Ravenstein, 1885).
Carrothers (1956)
A ____ and a ____ were incorporated into a study of
farm population migrations in the United States (Young, 1924)
§ No multiplication of masses, squaring of the distance is tantamount to
weighting its impact
Proportionality Factor, Distance Component
Variation of the ____ was used to delineate the trade areas of two competing
masses by estimating the volume of trade generated by the inhabitants of the
intervening space (Reilly, 1929, 1931)
Gravity Model
The ____ between these two adjacent trade centers identified
a location at which an individual is indifferent about which center he or she will
patronize.
Point of Equilibrium
____ and ____ were the first to revert to the early formulation of Carey
with a direct analogy between physical and social interaction
Stewart (1941), Zipf (1949)
- Extensive review of the gravity and potential models and
- synthesized a large amount of material available up to that time.
- Drawing from the works of Carroll and Bevis(1950), Dodd(1950), Ikie(1954), they
derived the gravity model
Isard Et Al. (1960)
o Air, rail, bus and auto traffic volumes (Alcaly, 1967)
o Test the effect of aggregation on the results yielded by the model
o The model is a macroscopic and inclusive, therefore, it’s powerful in describing
and predicting mas behavior of spatial interaction.
Modeling Multimodal Passenger Flows
Used to study the inhibiting influences of political boundaries upon spatial
interaction (Mackay, 1958)
Modeling Communication Flows
§ remarkable ability to mirror observed patterns of interaction
§ simple to compute and easy to understand intuitively
§ remarkable ability to describe and predict (although not explain) spatial
interaction
§ less satisfactory when mass is disaggregated
§ subject to different interpretations
Model Builder’s Viewpoint
§ perfect symmetry between explanation and prediction
§ absence of theory means no basis of discrimination among alternative
interpretations
§ gravity models are deterministic
Philosopher of Science’s Viewpoint
Underlying theory that can be associated with the gravity
model
Theory of Least Effort
The Gravity Model is ____ & no conceptual justification
Deterministic
