stplanr (version 0.1.4)

overline: Convert series of overlapping lines into a route network

Description

This function takes a series of Lines stored in a SpatialLinesDataFrame and converts these into a single route network.

Usage

overline(sldf, attrib, fun = sum, na.zero = FALSE, byvars = NA)

Arguments

sldf

A SpatialLinesDataFrame with overlapping elements

attrib

A character vector corresponding to the variables in sldf$ on which the function(s) will operate.

fun

The function(s) used to aggregate the grouped values (default: sum). If length of fun is smaller than attrib then the functions are repeated for subsequent attributes.

na.zero

Sets whether aggregated values with a value of zero are removed.

byvars

Character vector containing the column names to use for grouping

References

Rowlingson, B (2015). Overlaying lines and aggregating their values for overlapping segments. Reproducible question from http://gis.stackexchange.com. See http://gis.stackexchange.com/questions/139681/overlaying-lines-and-aggregating-their-values-for-overlapping-segments.

Examples

## Not run: 
# data(routes_fast)
# data(cents)
# rnet <- overline(sldf = routes_fast[1:7,], attrib = "length")
# plot(rnet)
# points(cents)
# lineLabels(sldf = rnet, "length")
# sum(routes_fast$length[1:7], na.rm = TRUE) # verify highest flow
# data(flowlines)
# plot(flowlines)
# aggflow <- overline(flowlines, attrib = "All")
# nrow(aggflow)
# aggflow2 <- overline(flowlines, attrib = "All", na.zero = TRUE)
# plot(aggflow2) # 8 lines
# sel <- as.logical(colSums(gEquals(flowlines, aggflow2, byid = TRUE)))
# flowlines_sub <- flowlines[!sel,]
# plot(flowlines_sub)
# flowlines_2way <- flowlines[sel,]
# library(maptools)
# flowlines_2way <- spChFIDs(flowlines_2way, as.character(100001:(nrow(flowlines_2way) + 100000)))
# flowlines_1way <- maptools::spRbind(flowlines_sub, flowlines_2way)
# overlaps <- over()
# nrow(overlaps)
# routes_fast$group = rep(1:3, length.out = nrow(routes_fast))
# rnet_grouped = overline(routes_fast, attrib = "length", byvars = "group")
# plot(rnet_grouped, col = rnet_grouped$group, lwd =
#   rnet_grouped$length / mean(rnet_grouped$length) * 3)
# ## End(Not run)