addRasterRGB: Add an RGB image as a layer

In leafem: 'leaflet' Extensions for 'mapview'

Add an RGB image as a layer

Description

Create a Red-Green-Blue image overlay from a RasterStack / RasterBrick or stars object based on three layers. 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 plagirized, i.e. copied from plotRGB. AddRasterRGB and addStarsRGB are aliases.

Usage

addRasterRGB(
  map,
  x,
  r = 3,
  g = 2,
  b = 1,
  quantiles = c(0, 1),
  domain = NULL,
  na.color = "#BEBEBE80",
  ...
)

addStarsRGB(
  map,
  x,
  r = 3,
  g = 2,
  b = 1,
  quantiles = c(0, 1),
  domain = NULL,
  na.color = "#BEBEBE80",
  ...
)

Arguments

map	a map widget object created from 'leaflet()“
x	a 'RasterBrick', 'RasterStack' or 'stars“ raster object
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, stretching is performed basing on 'domain' argument.
domain	the upper and lower values used for color stretching. This is used only if 'quantiles' is NULL. If both 'domain' and 'quantiles' are set to NULL, stretching is applied based on min-max values.
na.color	the color to be used for NA pixels
...	additional arguments passed on to addRasterImage

Author(s)

Tim Appelhans, Luigi Ranghetti

Examples

  require(raster)
  require(stars)
  require(plainview)
  require(leaflet)

  leaflet() %>%
    addTiles(group = "OpenStreetMap") %>%
    addRasterRGB(plainview::poppendorf, 4,3,2, group = "True colours") %>%
    addStarsRGB(st_as_stars(plainview::poppendorf), 5,4,3, group = "False colours") %>%
    addLayersControl(
      baseGroups = c("Satellite"),
      overlayGroups = c("True colours", "False colours"),
    )

leafem documentation built on Sept. 18, 2023, 1:06 a.m.