Get a Download ID.

Returns a download id and token, or null if a callback is specified.

UsageReturns, callback)DownloadId

An object containing download options with the following possible values:

  - image: The image to download.

  - name: a base name to use when constructing filenames.

  - bands: a description of the bands to download. Must be an array of dictionaries, each with the following keys:

    + id: the name of the band, a string, required.

    + crs: an optional CRS string defining the band projection.

    + crs_transform: an optional array of 6 numbers specifying an affine transform from the specified CRS, in row-major order:

[xScale, xShearing, xTranslation, yShearing, yScale, yTranslation]

    + dimensions: an optional array of two integers defining the width and height to which the band is cropped.

    + scale: an optional number, specifying the scale in meters of the band; ignored if crs and crs_transform is specified.

  - crs: a default CRS string to use for any bands that do not explicitly specify one.

  - crs_transform: a default affine transform to use for any bands that do not specify one, of the same format as the crs_transform of bands.

  - dimensions: default image cropping dimensions to use for any bands that do not specify them.

  - scale: a default scale to use for any bands that do not specify one; ignored if dimensions is specified.

  - region: a polygon specifying a region to download.

  - filePerBand: Whether to produce a different GeoTIFF per band (boolean). Defaults to true. If false, a single GeoTIFF is produced and all band-level transformations will be ignored.

  - id: deprecated, use image: ee.Image(id)

callbackFunction, optional

An optional callback. If not supplied, the call is made synchronously.