Chicago (version 1.0.3)

estimateDistFun: Estimate the Distance Function

Description

Estimates the function that models how the expected number of counts decreases with increasing distance.

Usage

estimateDistFun(cd, method = "cubic", plot = TRUE, outfile = NULL)

Arguments

cd

A chicagoData object.

method

Choice of method: "cubic" is currently the only allowed option, which fits a cubic function with linear extrapolation, on a log-log scale.

plot

Output a diagnostic plot.

outfile

If NULL, plot to current device. Otherwise, plot to the .pdf file outfile.

Value

An object of class chicagoData, with the parameters of the distance function present as params(cd)$distFunParams.

Details

By default, we look in 75 distance bins, and a cubic fit is used. For distances that lie outside of the bin boundaries, it is assumed that the function is log-linear, with continuity of f and its first derivative on the log-scale.

See Also

chicagoPipeline, plotDistFun

Examples

data(cdUnitTest)
estimateDistFun(cdUnitTest)