Add Cloud Optimised Geotiff (COG) to a leaflet map.

Usage

addCOG(
  map,
  url = NULL,
  group = NULL,
  layerId = NULL,
  resolution = 96,
  opacity = 0.8,
  options = leaflet::tileOptions(),
  colorOptions = NULL,
  pixelValuesToColorFn = NULL,
  autozoom = TRUE,
  rgb = FALSE,
  ...
)

Arguments

map: the map to add the COG to.
url: url to the COG file to render.
group: he name of the group this COG should belong to.
layerId: the layerId.
resolution: the target resolution for the simple nearest neighbor interpolation. Larger values will result in more detailed rendering, but may impact performance. Default is 96 (pixels).
opacity: image opacity.
options: see [leaflet](tileOptions).
colorOptions: list defining the palette, breaks and na.color to be used. Currently not used.
pixelValuesToColorFn: optional JS function to be passed to the browser. Can be used to fine tune and manipulate the color mapping. See examples & https://github.com/r-spatial/leafem/issues/25 for some examples. Currently not used.
autozoom: whether to automatically zoom to the full extent of the layer. Default is TRUE.
rgb: logical, whether to render Geotiff as RGB. Currently not used.
...: currently not used.

Value

A leaflet map object.

Details

This function will overlay Cloud Optimised Geotiff data from a remote url on a leaflet map. Like `addGeotiff` it uses the leaflet plugin 'georaster-layer-for-leaflet' to render the data. See `addGeotiff` for a bit more detail what that means.

Examples

if (interactive()) {
  library(leaflet)
  library(leafem)

  url = "https://sentinel-cogs.s3.us-west-2.amazonaws.com/sentinel-s2-l2a-cogs/46/X/DG/2022/8/S2B_46XDG_20220829_0_L2A/L2A_PVI.tif"

  leaflet() |>
    addTiles() |>
    leafem:::addCOG(
      url = url
      , group = "COG"
      , resolution = 512
      , autozoom = TRUE
    )
}