who-data

Data for who and who3 repos. This README describes the process to download and process who3 data. To do that, clone this repo, then run the following in the main repo directory:

devtools::load_all (".", export_all = FALSE)

This project currently processes data for the two cities of Accra, Ghana, and Kathmandu, Nepal. Most functions accept a single city argument as one of the two of these (without country specifications). Having downloaded and locally installed the package, the following lines are necessary to pre-process and locally save required data.

city <- "Kathmandu" # or Accra
hw <- who3_network (city) # way network
bus <- who3_bus_network (city)
bus <- who3_bus_centrality (city)
cent <- who3_centrality (city) # time-based centrality for motorcars
b <- who3_buildings (city)
netf <- who3_flow (city) # calculate pedestrian flows from buses and activity centres

The main results are then returned from an additional function which appends columns quantifying densities of motorcars, and equivalent dispersed values representing dispersal of pollutant away from vehicular sources of origin. The single additional parameter of this function specifies the width of a Gaussian diespersal kernel in metres.

netf <- who3_disperse_centrality (city, disperse_width = 200) 

That returns an sf-formatted data.frame with columns for pedestrian flows ("flow"), vehicular flows ("centrality"), and dispersed vehicular flows ("centrality_disp"). The direct exposure of pedestrians to vehicular emissions can then be obtained by multiplying flow * centrality_disp.