Google Earth Engine（GEE）——如何获取指定区域动画影像的指定波段信息

 通常我们对于一个影像的下载一般会选择直接合成一个真彩色，或者特定的颜色来完成，但是大部分情况下我们无法看到单个波段的情况，所以我们要使用一参数来完成指定波段的影像下载。我们首先看一下函数（蓝色部分为各波段信息）：

getDownloadURL(params, callback)

Get a download URL for small chunks of image data in GeoTIFF or NumPy format. Maximum request size is 32 MB, maximum grid dimension is 10000.

Use getThumbURL for RGB visualization formats PNG and JPG.

Returns returns a download URL, or undefined if a callback was specified.

Arguments:

this:image (Image):

The Image instance.

params (Object):

An object containing download options with the following possible values:

• name: a base name to use when constructing filenames. Only applicable when format is "ZIPPED_GEO_TIFF" (default) or filePerBand is true. Defaults to the image id (or "download" for computed images) when format is "ZIPPED_GEO