Plot a map with target locations — target

Function to plot the centroids of sites to be dated and shoreline isobases of employed displacement curves on a basemap. Defaults to displaying a light-weight version of the spatial coverage in south-eastern Norway. However, spatial geometries covering other regions can also be provided or temporarily downloaded with the function.

target_plot(
  targets = NA,
  isobases = sf::st_read(system.file("extdata/isobases.gpkg", package = "shoredate",
    mustWork = TRUE), quiet = TRUE),
  basemap = sf::st_read(system.file("extdata/naturalearth_basemap.gpkg", package =
    "shoredate", mustWork = TRUE), quiet = TRUE),
  crs_epsg = 32632,
  naturalearth_basemap = FALSE,
  naturalearth_zoom = c(20000, 20000),
  target_labels = TRUE,
  scalebar = TRUE,
  scalebar_width = 0.4,
  scalebar_style = "ticks",
  scalebar_location = "br",
  base_fill = "grey",
  base_col = NA,
  target_shape = 21,
  target_col = "black",
  target_fill = "red",
  target_size = 2.25,
  isobase_line = c(Horten = "solid", Porsgrunn = "solid", Tvedestrand = "solid", Arendal
    = "solid"),
  isobase_col = c(Arendal = "black", Porsgrunn = "darkgreen", Tvedestrand = "blue",
    Horten = "darkorange"),
  greyscale = FALSE
)

Arguments

targets: Objects of class sf representing the sites to be dated. The first column beyond geom is taken as site name.
isobases: Spatial lines as object of class sf representing the shoreline isobases. Defaults to isobases with a direction of 327 within the spatial limit in SE Norway, but create_isobases() can be used to create isobases with other directions that can then be passed to target_plot().
basemap: Object of class sf representing a background map. Defaults to a light-weight basemap for the spatial limit in SE Norway.
crs_epsg: Numeric value specifying the EPSG code of the coordinate reference system (CRS) to be used. Geometries with a different CRS will be re-projected. Defaults to 32632, which is WGS 84 / UTM zone 32N (EPSG:32632).
naturalearth_basemap: Logical value specifying if a background map should be downloaded to be used as a basemap. Downloaded files are stored with base::tempdir() and deleted when the R session is closed. If TRUE, overrides the basemap argument. Defaults to FALSE.
naturalearth_zoom: A vector of two numerical values specifying the amount of cropping that is done around provided targets when naturalearth_basemap is set to TRUE. Be aware of whether a projected or geographical CRS is specified in crs_epsg. Defaults to c(20000, 20000).
target_labels: Logical value specifying whether the targets should be labelled in the plot. Takes the first column beyond the one holding the geometries to represent names. If this is not present the targets are labelled by row number. Defaults to TRUE.
scalebar: Logical specifying whether a scale bar should be added to the plot. Defaults to TRUE.
scalebar_width: Numerical value specifying the width of the scale bar by passing it to the width_hint argument of ggspatial::annotation:scale(). Defaults to 0.4.
scalebar_style: Character value specifying the style of the scale bar by passing it to the style argument of ggspatial::annotation:scale(). Defaults to "ticks".
scalebar_location: Character value specifying the location of the scale bar on the plot by passing it to the location argument of ggspatial::annotation:scale(). Defaults to "br".
base_fill: Character value specifying the fill colour of the basemap. Defaults to "grey".
base_col: Character value specifying the outline colour of the basemap. Defaults to NA.
target_shape: Numerical value specifying the point shape that represent the centroids of the targets. Defaults to 21.
target_col: Character value specifying the colour parameter for the points that represent the centroids of the targets. Defaults to "black".
target_fill: Character value specifying the fill parameter for the points that represent the centroids of the targets. Defaults to "red".
target_size: Numerical value specifying the size of the points that represent the centroids of the targets. Defaults to 2.25.
isobase_line: Vector of character values specifying the linetype that is used to represent the isobases of the geologically derived displacement curves. Defaults to c("Horten" = "solid", "Porsgrunn" = "solid", "Tvedestrand" = "solid", "Arendal" = "solid").`
isobase_col: Vector of character values specifying the colours used for the lines that represent the isobases of the geologically derived displacement curves. Defaults to c("Arendal" = "black", "Porsgrunn" = "darkgreen", "Tvedestrand" = "blue", "Horten" = "darkorange").`
greyscale: Logical value indicating whether the plot should include colours or not. Overrides other graphical parameters When set to TRUE. Defaults to FALSE.

Value

A ggplot that displays a background map with the location of the shoreline isobases within the spatial coverage in south-eastern Norway, unless geometries for other regions are provided. If provided, the function also plots the position of target locations represented as centroids.

Examples

# Display the background map and default isobases
target_plot()