Graduated Links Layer

Plot a layer of graduated links. Links are plotted according to discrete classes of widths.

gradLinkLayer(
  x,
  df,
  xid = NULL,
  dfid = NULL,
  var,
  breaks = getBreaks(v = df[, var], nclass = 4, method = "quantile"),
  lwd = c(1, 2, 4, 6),
  col = "red",
  legend.pos = "bottomleft",
  legend.title.txt = var,
  legend.title.cex = 0.8,
  legend.values.cex = 0.6,
  legend.values.rnd = 0,
  legend.frame = FALSE,
  add = TRUE
)

Arguments

x: an sf object, a simple feature collection.
df: a data frame that contains identifiers of starting and ending points and a variable.
xid: names of the identifier variables in x, character vector of length 2, default to the 2 first columns. (optional)
dfid: names of the identifier variables in df, character vector of length 2, default to the two first columns. (optional)
var: name of the variable used to plot the links widths.
breaks: break values in sorted order to indicate the intervals for assigning the lines widths.
lwd: vector of widths (classes of widths).
col: color of the links.
legend.pos: position of the legend, one of "topleft", "top", "topright", "right", "bottomright", "bottom", "bottomleft", "left" or a vector of two coordinates in map units (c(x, y)). If legend.pos is "n" then the legend is not plotted.
legend.title.txt: title of the legend.
legend.title.cex: size of the legend title.
legend.values.cex: size of the values in the legend.
legend.values.rnd: number of decimal places of the values displayed in the legend.
legend.frame: whether to add a frame to the legend (TRUE) or not (FALSE).
add: whether to add the layer to an existing plot (TRUE) or not (FALSE).

Note

Unlike most of cartography functions, identifiers fields are mandatory.

Examples

library(sf)
mtq <- st_read(system.file("gpkg/mtq.gpkg", package="cartography"))
#> Reading layer `mtq' from data source 
#>   `/tmp/RtmpmpfIrO/temp_libpath18ee15f22a9e/cartography/gpkg/mtq.gpkg' 
#>   using driver `GPKG'
#> Simple feature collection with 34 features and 7 fields
#> Geometry type: MULTIPOLYGON
#> Dimension:     XY
#> Bounding box:  xmin: 690574 ymin: 1592536 xmax: 735940.2 ymax: 1645660
#> Projected CRS: WGS 84 / UTM zone 20N
mob <- read.csv(system.file("csv/mob.csv", package="cartography"))
# Create a link layer - work mobilities to Fort-de-France (97209)
mob.sf <- getLinkLayer(x = mtq, df = mob[mob$j==97209,], dfid = c("i", "j"))
# Plot the links - Work mobility
plot(st_geometry(mtq), col = "grey60",border = "grey20")
gradLinkLayer(x = mob.sf, df = mob,
              legend.pos = "topright",
              var = "fij", 
              breaks = c(109,500,1000,2000,4679), 
              lwd = c(1,2,4,10),
              col = "#92000090", add = TRUE)

Arguments

Note

See also

Examples