GEE学习笔记2：加载Landsat8 和Sentinel影像数据

从GEE数据集导入的数据

边界加载

//hlj1为导入的shp数据
var roi = hlj1;
Map.centerObject(roi,5);
var empty = ee.Image().toByte();
var outline = empty.paint({
 featureCollection:roi,  // 筛选的colletion
 color:0, //颜色透明
 width:3  //边界宽度
});
//绘制红色边界
Map.addLayer(outline, {palette: "ff0000"}, "outline");
//定义时间节点
var startdate = ee.Date.fromYMD(2016,5,1);
var enddate = ee.Date.fromYMD(2016,10,1);

加载Sentinel 1数据

//s1为从GEE 数据集导入的Sentinel 1数据
var Sentinel1_VV =  s1.filterBounds(roi)
                    .filterDate(startdate, enddate)
                    .filter(ee.Filter.eq('instrumentMode', 'IW'))
                    .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VV'))
                    .select('VV')
                     .median();
​
var Sentinel1_VH =  s1.filterBounds(roi)
                    .filterDate(startdate, enddate)
                    .filter(ee.Filter.eq('instrumentMode', 'IW'))
                    .filter(ee.Filter.listContains('transmitterReceiverPolarisation',                       'VH'))
                   
                    .select('VH')
                    .median();

加载Sentinel 2

//去云函数
var cloudfunction_ST2 = function(image){
  //use add the cloud likelihood band to the image
  var quality = image.select("QA60").unmask();
  //get pixels above the threshold
  var cloud01 = quality.gt(0);
  //create a mask from high likelihood pixels
  var cloudmask = image.mask().and(cloud01.not());
  //mask those pixels from the image
  return image.updateMask(cloudmask);
};
//s2为从GEE 数据集导入的Sentinel 2数据
var Sentinel2 = s2.filterBounds(roi)
                .filterDate(startdate, enddate)
                .map(cloudfunction_ST2)
                 .median();

加载Landsat 8

//去云 
function maskL8sr(image) {
  var cloudShadowBitMask = (1 << 3);
  var cloudsBitMask = (1 << 5);
  var qa = image.select('pixel_qa');
  var mask = qa.bitwiseAnd(cloudShadowBitMask).eq(0)
                .and(qa.bitwiseAnd(cloudsBitMask).eq(0));
  return image.updateMask(mask);
}
//L8为从GEE 数据集导入的Landsat 8数据
var landsat8Image =L8.filterBounds(roi)
                    .filterDate(startdate, enddate)
                   .median();