viewRGB {mapview}

Red-Green-Blue map view of a multi-layered Raster object

Description

Make a Red-Green-Blue plot based on three layers (in a RasterBrick, RasterStack). Three layers (sometimes referred to as "bands" because they may represent different bandwidths in the electromagnetic spectrum) are combined such that they represent the red, green and blue channel. This function can be used to make 'true (or false) color images' from Landsat and other multi-band satellite images. Note, this text is plagiarized, i.e. copied from plotRGB.

Usage

viewRGB(
  x,
  r = 3,
  g = 2,
  b = 1,
  quantiles = c(0.02, 0.98),
  map = NULL,
  maxpixels = mapviewGetOption("mapview.maxpixels"),
  map.types = mapviewGetOption("basemaps"),
  na.color = mapviewGetOption("na.color"),
  layer.name = NULL,
  method = c("bilinear", "ngb"),
  ...
)

Arguments

x

a RasterBrick, RasterStack

r

integer. Index of the Red channel/band, between 1 and nlayers(x)

g

integer. Index of the Green channel/band, between 1 and nlayers(x)

b

integer. Index of the Blue channel/band, between 1 and nlayers(x)

quantiles

the upper and lower quantiles used for color stretching. If set to NULL, no stretching is applied.

map

the map to which the layer should be added

maxpixels

integer > 0. Maximum number of cells to use for the plot. If maxpixels < ncell(x), sampleRegular is used before plotting.

map.types

character spcifications for the base maps. see https://leaflet-extras.github.io/leaflet-providers/preview/ for available options.

na.color

the color to be used for NA pixels

layer.name

the name of the layer to be shown on the map

method

Method used to compute values for the resampled layer that is passed on to leaflet. mapview does projection on-the-fly to ensure correct display and therefore needs to know how to do this projection. The default is 'bilinear' (bilinear interpolation), which is appropriate for continuous variables. The other option, 'ngb' (nearest neighbor), is useful for categorical variables.

...

additional arguments passed on to mapView

Author(s)

Tim Appelhans

Examples

if (interactive()) {
  library(raster)
  library(plainview)

  viewRGB(plainview::poppendorf, 4, 3, 2) # true-color
  viewRGB(plainview::poppendorf, 5, 4, 3) # false-color
}