Dagstuhl Summer School on movement patterns, 2017-07-11

Outline

  • Introductory comments
  • Demonstration
  • Discussion

Introductory comments

The title

  • Was initially titled "The Propensity to Cycle Tool: from conception in the clouds to implementation on the ground"

What do I mean by 'scalable'

  • Large surface area (countries, planets)
  • Reproducible, e.g. for infinite new scenarios of future
  • Accessible - so results can 'scale' to be seen and used interactively by millions of people
  • Resilient: methods can operate in data rich and data poor environments
  • Rationale: a 'rolled-out' simple method can have a greater impact than a non-scalable complex one

Real world problem

Source: Warrington Cycle Campaign

Context (see the 'CWIS' report)

  • 2 years in the making, the PCT is now part of the Cycling and Walking Infrastructure Strategy (CWIS)
  • Mentioned in the forword of this legally binding document
  • Being used by dozens of local authorities to design strategic cycling networks

The propensity to cycle tool method

Source: (Lovelace et al. 2017)

Code as a tool/language (source: UseR2016)

# Download all code and data to reproduce example
git clone git@github.com:homeRangeOD/homeRangeOD

## Cloning into 'homeRangeOD'...
cp -r homeRangeOD/input-data/* . # move the data

As a language

  • As a language: to communicate (Knuth 1984)
library(stplanr)
oas_lds = readRDS("oas_lds.Rds")
wpz_lds = readRDS("wpz_lds.Rds")
flow = readr::read_csv("f_lds.csv")
f_sp = od2line(flow = flow, zones = oas_lds, destinations = wpz_lds)

That also 'gets stuff done' (Thanks: Jack Snoeyink)

library(tmap)
tmap_mode("view")
## tmap mode set to interactive viewing
qtm(oas_lds) +
  qtm(wpz_lds, symbols.col = "red", symbols.size = 2) +
  qtm(f_sp)

Demonstration

For England we have OD data

For Spain we do not - so model it

How to model OD data? Spatial interaction model

  • Mature method for estimating flow (Kariel 1968; Wilson 1971)
  • Can be extended towards agent-based modelling (ABM) (Wu, Birkin, and Rees 2008; Lovelace and Dumont 2016)
  • Can be calibrated with 'Big Data' (Lovelace et al. 2016)
  • Theotical advance: the radiation model (Simini et al. 2012)
library(stplanr)
cents$pop = 1:nrow(cents)
plot(cents, cex = cents$pop)

The radiation model (Simini et al. 2012)

flow_est = od_radiation(p = cents, pop_var = "pop")
plot(flow_est, lwd = flow_est$flow)

Discussion

Technical issues

  • For scalability generalisability is vital
  • software engineering/compsci approach
  • But political leadership vital

Wider issues

  • Links with the Cycling Infrastructure Prioritisation Toolkit (CyIPT)
  • How to institutionalise the open (data, science) approach
  • Citizen science / crowd funded add-ons
  • Next case study cities?

Crowd-sourcing transport planning?

Source: streetmix.net

Questions / Issues to consider

  • How to move from simulation / theory to implementation?
  • Where does prediction and validation fit in?
    • How to do natural experiments in this area?
  • How can ecological theory / models inform transport simulations?
    • Defining and modelling 'home ranges' (activity spaces)
    • Modelling GPS traces ('bread crumb data')
    • Group behaviour / 'contagion' (if you cycle, I'll cycle)

Plug: Open source geocomputation book

Abstract

It is important to know where people travel for a number of reasons. Most important among these is the urgent need to transition away from fossil fuels: models of travel patterns can help identify the most effective interventions to make this happen.

This paper explores globally scalable methods for generating estimates of travel patterns that build on areal and point-based data to estimate movements down to the road network level currently, and under scenarios of the change. The presentation is based on my experience developing the Propensity to Cycle Tool (PCT) and scaling it across all areas and major cyclable roads in England (see pct.bike) and recent experiments extending it internationally with a case study in Seville, Spain.

Methodologically I will explore the possibility of extending the methods to be dynamic and multi-modal, themes that will be prominent during the summer school.

References

Kariel, Herbert G. 1968. “Student Enrollment and Spatial Interaction.” The Annals of Regional Science 2 (1): 114–27.

Knuth, Donald Ervin. 1984. “Literate Programming.” The Computer Journal 27 (2): 97–111.

Lovelace, Robin, and Morgane Dumont. 2016. Spatial Microsimulation with R. CRC Press. http://robinlovelace.net/spatial-microsim-book/.

Lovelace, Robin, Mark Birkin, Philip Cross, and Martin Clarke. 2016. “From Big Noise to Big Data: Toward the Verification of Large Data Sets for Understanding Regional Retail Flows.” Geographical Analysis 48 (1): 59–81. doi:10.1111/gean.12081.

Simini, Filippo, Marta C González, Amos Maritan, and Albert-László Barabási. 2012. “A Universal Model for Mobility and Migration Patterns.” Nature, February, 8–12. doi:10.1038/nature10856.

Wilson, AG. 1971. “A Family of Spatial Interaction Models, and Associated Developments.” Environment and Planning 3 (January): 1–32. http://www.environment-and-planning.com/epa/fulltext/a03/a030001.pdf.

Wu, B.M., Mark M.H. Birkin, and P.H. Rees. 2008. “A Spatial Microsimulation Model with Student Agents.” Computers, Environment and Urban Systems 32 (6): 440–53. doi:10.1016/j.compenvurbsys.2008.09.013.