dd_fit_stations: dd_fit_stations
In mpadge/distdecay: Calculate Distance Decay Functions

Fit a generalised exponential decay model to data from one station

1 2	dd_fit_stations(city, from = TRUE, lower = 0, upper = 1, mi = FALSE, expmod = TRUE, osm = TRUE, plot = FALSE)

`city`	City for which model is to be fitted
`from`	Analyse decay functions for trips from each station. If `FALSE`, analyse for trips to each station.
`lower`	Lower limit (0-1) for distance cutoff used to calculate covariances (see details)
`upper`	Upper limit (0-1) for distance cutoff used to calculate covariances (see details)
`mi`	If `TRUE`, fit decay functions for mutual information, otherwise fit covariances.
`expmod`	If `TRUE`, fit exponential decay models, otherwise fit power-law decays.
`osm`	If `FALSE`, use straight-line distances for distance decay parameters, otherwise street network distances.
`plot`	If `TRUE`, plot decay function

A data.frame of four values: id, the ID of the station; k, the width parameter of the exponential decay; b, the value of the exponent; and ss, the standardised sum of squared residuals.

Power-law fits (with expmod = FALSE) are not reliable at all. The decays really are not power-laws, so this ought not be used.

mpadge/distdecay documentation built on May 24, 2019, 6:08 a.m.