od_jitter: Move desire line end points within zone to avoid all trips...

In od: Manipulate and Map Origin-Destination Data

Move desire line end points within zone to avoid all trips going to a single centroid

Description

These functions tackle the problem associated with OD data representing movement to and from large zones. Typically the associated desire lines start and end in one point per zone. This function produces desire lines that can start and end anywhere (or at predefined points) within each zone. See issue #11 for details.

Usage

od_jitter(
  od,
  z,
  subpoints = NULL,
  code_append = "_ag",
  population_column = 3,
  max_per_od = 1e+05,
  keep_ids = TRUE,
  integer_outputs = FALSE,
  zd = NULL,
  subpoints_o = NULL,
  subpoints_d = NULL,
  disag = FALSE
)

Arguments

od	An origin-destination data frame
z	Zones representing origins and destinations
subpoints	Points, lines or polygons within the zones. These define the OD data start/end points.
code_append	The name of the column containing aggregate zone names
population_column	The column containing the total population (if it exists)
max_per_od	Maximum flow in the population_column to assign per OD pair. This only comes into effect if there are enough subpoints to choose from.
keep_ids	Should the origin and destination ids be kept? TRUE by default, meaning 2 extra columns are appended, with the names o_agg and d_agg containing IDs from the original OD data.
integer_outputs	Should integer outputs be returned? FALSE by default. Note: there is a known issue when integer results are generated. See https://github.com/ITSLeeds/od/issues/31 for details.
zd	Zones with ids matching the destination codes in input OD data
subpoints_o	Points within origin zones representing possible destinations
subpoints_d	Points within destination zones representing possible destinations
disag	Should the od_disaggregate function be used as a 'back end' where possible? FALSE by default. See https://github.com/ITSLeeds/od/issues/39.

Value

An sf data frame

Examples

# Basic example
od = od_data_df
z = od_data_zones_min
dlr = od_jitter(od, z) # desire_lines_random
desire_lines = od_to_sf(od, z)
plot(z$geometry)
plot(dlr["all"], add = TRUE, lwd = 3)
dlr$all
desire_lines$all
plot(desire_lines["all"], add = TRUE, lwd = 5)

# Example showing use of subpoints
subpoints_o = sf::st_sample(z, 200)
subpoints_d = sf::st_sample(z, 100)
dlr_d = od_jitter(od, z, subpoints_o = subpoints_o, subpoints_d = subpoints_d)
plot(z$geometry)
plot(dlr_d$geometry, add = TRUE)
plot(subpoints_o, add = TRUE)
plot(subpoints_d, col = "red", add = TRUE)
plot(desire_lines, add = TRUE, lwd = 5)
# mapview::mapview(desire_lines) + dlr + z # interactive map
sp = sf::st_sample(z, 100)
dlr2 = od_jitter(desire_lines, z, subpoints_o = sp, subpoints_d = sp)
plot(z$geometry)
plot(sp, add = TRUE)
plot(dlr2, add = TRUE, lwd = 3)
plot(desire_lines, add = TRUE, lwd = 5)

# Example showing jittering with origin and destination zones
od = od_data_df2
z = sf::st_buffer(od_data_centroids2, dist = 1000)
zd = sf::st_buffer(od_data_destinations, dist = 300)
zd = zd[zd[[1]] %in% od[[2]], ]
desire_lines = od_to_sf(od, od_data_centroids2, zd = od_data_destinations)
dlr = od_jitter(od, z, zd = zd)
plot(z$geometry)
plot(od_data_centroids2$geometry, add = TRUE)
plot(od_data_destinations$geometry, add = TRUE)
plot(zd$geometry, add = TRUE)
plot(dlr, add = TRUE, lwd = 3)
plot(desire_lines, add = TRUE, lwd = 5)

# Larger example with only subset of matching zones
# od = od_data_df_medium
# od_sf = od_to_sf(od, od_data_zones)
# dlr3 = od_jitter(od_sf, od_data_zones)
# plot(od_sf[od$all > 200, 1])
# plot(dlr3[od$all > 200, 1])
# mapview::mapview(od_sf$geometry[od$all > 200])

od documentation built on Sept. 11, 2024, 9:04 p.m.