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Preferred citation style for this presentation. Frei, A. (2006) Measuring activity spaces, social networks geographies and biographies: some methodological and empirical results , presentation at the COST 355 – WG3 meeting, Prague, October 2006.
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Preferred citation style for this presentation • Frei, A. (2006) Measuring activity spaces, social networks geographies and biographies: some methodological and empirical results, presentation at the COST 355 – WG3 meeting, Prague, October 2006.
Measuring activity spaces, social networks geographies and biographies: some methodological and empirical results A Frei IVT ETH Zürich October 2006
Trends: Road travel time scaled Switzerland (1950 & 2000) Scherer, 2004
Trends: Quality controlled prices of the mean new Swiss car Frei, 2005
Trends: Real price of telecommunication Adapted from FCC (2001)
Measures • Requirements: • Low dimensional (scalar) • Describe size, orientation and spread • Consistency with behavioural possibilities (theoretical intent) • Ease of calculation
How to measure ? • Parametric: • 95% confidence ellipse (form and type of distribution) • Semiparametric: • Inclusion geometries (form of geometry) • (Weighted) shortest path networks (structure of path) • (Percentage) Minimum convex poligons (convexity) • Kernel density estimator (form of estimator)
Measures: Confidence ellipse Schönfelder, 2006
Measures: Minimum convex polygons (MCP) • MCP Percentage MCP Schönfelder, 2006
Measures: Kernel densities Schönfelder, 2006
Measures: Shortest path network Schönfelder, 2006
Measures: Weighted shortest path network Schönfelder, 2006
Measures: Inclusion geometries • Find: • min Ai(i1 ..... in) • s.t. • Area Ai covering p% of all observed points • with: • i : Type of geometry (Ellipse, bean, Cassini ...) • p : Predetermined share, e.g. 95%
How do we explain travel and what is missing ? • Distribution of activities • Distribution of land use patterns • Generalised costs on the available infrastructure • Budget constraints • Capability constraints
Items to capture the social network geographies • Name generators • Name interpreters • Type and length of contact • Frequency by mode of contact • Home location • Second homes • Detailed descriptions of face-to-face contacts
Items to characterise the mobility biography • Home and second home locations • Work and school locations • Household composition • Mobility tools • Main mode (to work/school) • (Major holidays) • Personal income • Household income
Data available – Name generator and interpreter • ifmo: • “Persons with whom you had contact” • (f-to-f frequency, location, mobility biography) • DfT: • Family, non-local friends, most important persons • (location, frequency by mode, mobility biography) • COST 355: • Important people, people with leisure contacts • (location, frequency by mode, mobility biography)
18 to 39 years 40 to 59 years 60 years and more Residential mobility
Distribution of the social geographies Germany: 357; U.S.A: 9’629 [103 km2]
Assessment: Measuring activity spaces • Wide-ranging distributed places can be measured with the confidence ellipse • The symmetry of this measurement leads to too big spaces • Inclusion geometries can relief the symmetry problem
Results from the initial models • Biography has an impact on the number of contacts given • Strong distance decay of contact frequency • Strong distance effects on contact mode share • Biography affects the size of network geography
Literatur • Axhausen, K.W. (2005) Activity spaces, biographies, social networks and their welfare gains and externalities: Some hypothesis and empirical results, PROCESSUS Colloquium, Toronto, June 2005. • Carosio, A., C. Dolci and M. Scherer (2005) Erreichbarkeitsveränderungen in der Schweiz: Eine kartographische Darstellung, in K.W. Axhausen and L. Hurni (eds.) Zeitkarten Schweiz 1950-2000, Chapter 3, IVT and IKA, ETH Zürich, Zürich. • FCC (2001) Long distance telecommunication industry, FCC, Washington, D.C. • Frei, A. (2005) Was hätte man 1960 für einen Sharan bezahlt?, MSc thesis, IVT, ETH Zürich, Zürich.
Items to capture social content • Detailed purpose coding • Social purpose and obligations fulfilled with it • Beneficiaries of the activity • Composition of the party • Prior locations • Distribution of the travel and activity costs • Planning horizon • Number of previous visits to that location • Secondary activities