我是谷歌地球引擎的新手,对javascript不太熟悉。我想按图层中的每个日期显示 Sentinel 2 的清除图像(B4、B3、B2 波段)(每个图层代表每个日期)。代码如下所示,但总是得到错误'no Band 4,constant band'。谁能帮我解决这个问题?谢谢!
var lakes=table.geometry();
Map.centerObject(lakes, 15);
function maskS2clouds(image) {
var qa = image.select('QA60');
// Bits 10 and 11 are clouds and cirrus, respectively.
var cloudBitMask = 1 << 10;
var cirrusBitMask = 1 << 11;
// Both flags should be set to zero, indicating clear conditions.
var mask = qa.bitwiseAnd(cloudBitMask).eq(0)
.and(qa.bitwiseAnd(cirrusBitMask).eq(0));
return image.updateMask(mask).divide(10000);
}
var start = ee.Date('2015-06-20');
var finish = ee.Date('2018-06-01');
var collection = ee.ImageCollection('COPERNICUS/S2')
.filterDate(start, finish)
.filterBounds(lakes)
.filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 10))
.map(maskS2clouds);
var rgbVis = {
min: 0.0,
max: 0.3,
bands: ['B4', 'B3', 'B2'],
};
function addImage(imageL) { // display each image in collection
var id = imageL.id;
var image = ee.Image(imageL.id);
Map.addLayer(image.select(['B4','B3','B2']).clip(lakes),rgbVis,id)
}
collection.evaluate(function(collection) { // use map on client-side
print(collection.features);
collection.features.map(addImage);
})