lonlat: Add longitude latitude lines to a plot

In graticule: Meridional and Parallel Lines for Maps

Add longitude latitude lines to a plot

Description

Use the coordinates of the input raster to generate coordinate rasters, these are then used in a contour plot.

Usage

lonlat(
  x,
  na.rm = FALSE,
  lon = FALSE,
  lat = FALSE,
  ...,
  plot = TRUE,
  add = TRUE
)

Arguments

x	input raster
na.rm	logical, remove missing values from generated coordinates
lon	if TRUE, only longitude plotted
lat	if TRUE (and 'lon = FALSE') only latitude plotted
...	passed to [graphics::contour()]
plot	logical, plot the result
add	logical, add to current plot or instantiate one

Details

Plot is added to an existing plot by default.

Value

RasterBrick of the longitude and latitude values, two layers

(invisibly) the raster (RasterBrick) object with longitude and latitude values of the input as two layers, otherwise this function used for side-effect (drawing on a plot)

Examples

plot(c(-180, 180), c(-90, 90))
lonlat(raster::raster())

p <- raster::projectExtent(raster::raster(), "+proj=igh")
lonlat(p, add = FALSE)
lonlat(p, levels = seq(-180, 180, by  =15), add = FALSE)

lonlat(p, levels = seq(-180, 180, by = 5), add = FALSE, lon = TRUE)
lonlat(p, levels = seq(-180, 180, by = 15), add = TRUE, lat = TRUE)

graticule documentation built on Sept. 25, 2023, 5:06 p.m.