Add stars layer to a leaflet map

Usage

addStarsImage(
  map,
  x,
  band = 1,
  colors = "Spectral",
  opacity = 1,
  attribution = NULL,
  layerId = NULL,
  group = NULL,
  project = FALSE,
  method = c("auto", "bilinear", "near", "average", "mode", "cubic", "cubicspline",
    "lanczos", "sum", "min", "q1", "median", "q3", "max", "rms"),
  maxBytes = 4 * 1024 * 1024,
  options = gridOptions(),
  data = getMapData(map),
  ...
)

Arguments

map

a mapview or leaflet object.

x

a stars layer.

band

the band number to be plotted.

colors

the color palette (see colorNumeric) or function to use to color the raster values (hint: if providing a function, set na.color to "#00000000" to make NA areas transparent). The palette is ignored if x is a SpatRaster with a color table or if it has RGB channels.

opacity

the base opacity of the raster, expressed from 0 to 1

attribution

the HTML string to show as the attribution for this layer

layerId

the layer id

group

the name of the group this raster image should belong to (see the same parameter under addTiles)

project

if TRUE, automatically project x to the map projection expected by Leaflet (EPSG:3857); if FALSE, it's the caller's responsibility to ensure that x is already projected, and that extent(x) is expressed in WGS84 latitude/longitude coordinates

method

character. Method used for estimating the new cell values of a SpatRaster. One of:

bilinear: bilinear interpolation (3x3 cell window). This is used by default if the first layer of x is not categorical

average: This can be a good choice with continuous variables if the output cells overlap with multiple input cells.

near: nearest neighbor. This is used by default if the first layer of x is categorical. This method is not a good choice for continuous values.

mode: The modal value. This can be a good choice for categrical rasters, if the output cells overlap with multiple input cells.

cubic: cubic interpolation (5x5 cell window).

cubicspline: cubic B-spline interpolation. (5x5 cell window).

lanczos: Lanczos windowed sinc resampling. (7x7 cell window).

sum: the weighted sum of all non-NA contributing grid cells.

min, q1, median, q3, max: the minimum, first quartile, median, third quartile, or maximum value.

rms: the root-mean-square value of all non-NA contributing grid cells.

maxBytes

the maximum number of bytes to allow for the projected image (before base64 encoding); defaults to 4MB.

options

a list of additional options, intended to be provided by a call to gridOptions

data

the data object from which the argument values are derived; by default, it is the data object provided to leaflet() initially, but can be overridden.

...

currently not used.

Details

This is an adaption of addRasterImage. See that documentation for details.

Note, method auto, the default, will choose between near for factorial and bilinear for numeric data. All other methods need to be set manually.

Examples

# \donttest{
library(stars)
library(leaflet)

tif = system.file("tif/L7_ETMs.tif", package = "stars")
x = read_stars(tif)
leaflet() %>%
  addProviderTiles("OpenStreetMap") %>%
  addStarsImage(x, project = TRUE)
#> Warning: no_data_value not set: missing values will appear as zero values

# }