Google Earth Engine (GEE) - Draw a map of the research area of the paper on GEE (color)

The function used this time: the total function of counting the number of images

size()

Returns the number of elements in the collection.

Arguments:

this:collection (FeatureCollection):

The collection to count.

Returns: Integer

count()

Reduces an image collection by calculating the number of images with a valid mask at each pixel across the stack of all matching bands. Bands are matched by name.

Reduce the set of images by counting the number of images with a valid mask on each pixel in the stack of all matching bands . Bands are matched by name. 

Arguments:

this:collection (ImageCollection):

The image collection to reduce.

Returns: Image

Code: You can change your own research area by yourself

//加载我们的影像
var CHINA = ee.FeatureCollection('users/bqt2000204051/CHINA').geometry();
//加载指定的研究区到map上
Map.addLayer(CHINA, {'color':'grey'