本次就是利用Landsat计算ndvi、ndwi、ndbi来进计算和展示的，我们特别是在计算Landsat7的时候会出现一些问题，这里给大家展示的是一个错误的案例，大家可以通过调节代码来继续分析。
代码：
/**** Start of imports. If edited, may not auto-convert in the playground. ****/var roi = ee.FeatureCollection("users/vaibhavpuri/NCR");/***** End of imports. If edited, may not auto-convert in the playground. *****/var startYear = 2000;var endYear = 2001;var startDate = ee.Date.fromYMD(startYear, 1, 1);var endDate = startDate.advance(1,year);// print(startDate, endDate)// Cloud Maskvar cloudMaskL7 = function(image) {var dilatedCloud = (1 << 1)var cloud = (1 << 3)var cloudShadow = (1 << 4)var qa = image.select(QA_PIXEL);var mask = qa.bitwiseAnd(dilatedCloud).and(qa.bitwiseAnd(cloud)).or(qa.bitwiseAnd(cloudShadow))// var mask = qa.bitwiseAnd(dilatedCloud).eq(0).an
