Early morning timetable (#22)

CyclingImpedances.R

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+# Using a network created by 'NetworkGenerator.R', add impedances for 
+# calculating cycling accessibility
+
+# Assumes input network is a one-way network that includes elevation, 
+# and that one-way daily traffic volumes are available
+
+addImpedances <- function() {
+
+  # Parameters -----------------------------------------------------------------
+  # Input network, to which cycling impedances are to be added, with layer names
+  # input.network <- "./output/test/network.sqlite"
+  input.network <- "./output/test/melbourne_network.sqlite"  #<<< OLD VERSION FOR TESTING
+  input.node.layer <- "nodes"
+  input.link.layer <- "links"
+
+  # Traffic file, with links layer name - file must match input.network, 
+  # and with a 'total_vol' column containing 1-way daily traffic
+  # traffic.file <- "./output/test/network_traffic.sqlite"
+  traffic.file <- "./output/test/links_with_traffic.sqlite" #<<< OLD VERSION FOR TESTING
+  traffic.link.layer <- "cars_aht" 
+
+  # Traffic multiplier - where volumes are for a sample of traffic only (eg
+  # multiplier of 20 if the volumes are a 5% sample; use 1 if full volumes)
+  traffic.multiplier <- 10
+
+  # Output location - same directory as input.network
+  output.location <- paste0(path_dir(input.network), "/networkWeighted.sqlite")
+
+
+  # Packages and functions -----------------------------------------------------
+  library(dplyr)
+  library(sf)
+  library(fs)
+  library(osmextract)
+  library(stringr)
+
+  dir_walk(path="./functions/",source, recurse=T, type = "file")
+
+
+  # Load input network and traffic file ----------------------------------------
+  input.nodes <- st_read(input.network, layer = input.node.layer)  
+  input.links <- st_read(input.network, layer = input.link.layer)
+  traffic.links <- st_read(traffic.file, layer = traffic.link.layer)
+
+
+  # Add LTS and its impedance --------------------------------------------------
+  echo("Adding daily traffic volumes\n")
+  networkTraffic <- addTraffic(input.nodes,
+                               input.links, 
+                               traffic.links, 
+                               traffic.multiplier)
+  ## TO DO - maybe traffic can just be joined on link_id?  See whether traffic
+  ## file neatly uses the link_id's from the one-way input (also in cycling-adoption)
+
+  echo("Adding LTS and its impedance\n")
+  networkLTS <- addLTS(networkTraffic[[1]], networkTraffic[[2]])
+
+
+  # Add slope impedance --------------------------------------------------------
+  echo("Adding slope impedance")
+  networkSlope <- addSlopeImped(networkLTS[[1]], networkLTS[[2]])
+
+
+  # Add surface impedance --------------------------------------------------------
+  echo("Adding surface impedance")
+  networkSurf <- addSurfImped(networkSlope[[1]], networkSlope[[2]])
+
+
+  # Calculate total weight -----------------------------------------------------
+  echo("Calculating cycling weight")
+  networkWeighted <- 
+    list(networkSurf[[1]],
+         networkSurf[[2]] %>%
+           mutate(cycle.weight = length + LTS_imped + slope_imped + surf_imped))
+
+
+  # write output ---------------------------------------------------------------
+  st_write(networkWeighted[[1]], "./output/test/networkWeighted.sqlite", layer = "nodes")
+  st_write(networkWeighted[[2]], "./output/test/networkWeighted.sqlite", layer = "links")
+
+}