smooth_with_cutoffs: Identify and smooth-out anomalous gradient values

In Robinlovelace/cyclestreets: Cycle Routing and Data for Cycling Advocacy

Description

When distance_cutoff and gradient_cutoff thresholds are both broken for route segments, this function treats them as anomalous and sets the offending gradient values to the mean of the n segments closest to (in front of and behind) the offending segment.

Usage

smooth_with_cutoffs(
  gradient_segment,
  elevation_change,
  distances,
  distance_cutoff = 50,
  gradient_cutoff = 0.1,
  n = 3
)

Arguments

gradient_segment	The gradient for each segment from CycleStreets.net
elevation_change	The difference between the maximum and minimum elevations within each segment
distances	The distance of each segment
distance_cutoff	Distance (m) used to identify anomalous gradients
gradient_cutoff	Gradient (%, e.g. 0.1 being 10%) used to identify anomalous gradients
n	The number of segments to use to smooth anomalous gradents. The default is 3, meaning segments directly before, after and including the offending segment.

Examples

f = system.file(package = "cyclestreets", "extdata/journey.json")
obj = jsonlite::read_json(f, simplifyVector = TRUE)
rsf = json2sf_cs(obj, cols = c("distances"))
rsf$gradient_segment
rsf$elevation_change
rsf$distances
smooth_with_cutoffs(rsf$gradient_segment, rsf$elevation_change, rsf$distances)
smooth_with_cutoffs(rsf$gradient_segment, rsf$elevation_change, rsf$distances, 20, 0.05)
smooth_with_cutoffs(rsf$gradient_segment, rsf$elevation_change, rsf$distances, 200, 0.02)
smooth_with_cutoffs(rsf$gradient_segment, rsf$elevation_change, rsf$distances, 200, 0.02, n = 5)

Robinlovelace/cyclestreets documentation built on June 26, 2021, 11:22 p.m.