GEE初探

这是GEE中的一个案例，用于长时序地表温度的统计计算，作者 Sofia Ermida ([e-mail]; @ermida_sofia)

Ermida, S.L., Soares, P., Mantas, V., Göttsche, F.-M., Trigo, I.F., 2020.   Google Earth Engine open-source code for Land Surface Temperature estimation from the Landsat series. Remote Sensing, 12 (9), 1471; https://doi.org/10.3390/rs12091471

var LandsatLST = require('users/sofiaermida/landsat_smw_lst:modules/Landsat_LST.js')

// link to the code that computes broad-band emissivity

var BBE = require('users/sofiaermida/landsat_smw_lst:modules/broadband_emiss.js')

// select region of interest, date range, and landsat satellite

var site = ee.Geometry.Point([-116.01947,36.62373]);

var geometry = site.buffer(30);

var date_start = '1982-08-01';

var date_end = '2020-01-31';

var use_ndvi = true;

// compute the LST for each Landsat

var L8coll = LandsatLST.collection('L8', date_start, date_end, geometry, use_ndvi);

var L7coll = LandsatLST.collection('L7', date_start, date_end, geometry, use_ndvi);

var L5coll = LandsatLST.collection('L5', date_start, date_end, geometry, use_ndvi);

var L4coll = LandsatLST.collection('L4', date_start, date_end, geometry, use_ndvi);

// compute broadband emissivity

L8coll = L8coll.map(BBE.addBand(true))

L7coll = L7coll.map(BBE.addBand(true))

L5coll = L5coll.map(BBE.addBand(true))

L4coll = L4coll.map(BBE.addBand(true))

// get bands for each landsat in one collection

var getband = function(landsat, bandname){

 var wrap = function(image){

   return image.select(bandname).rename(bandname.concat('_').concat(landsat))

 }

 return wrap

}

// merge all Landsat LST collections for the chart

var bandname = 'LST'

var LandsatColl = L8coll.map(getband('L8',bandname));

LandsatColl = LandsatColl.merge(L7coll.map(getband('L7',bandname)));

LandsatColl = LandsatColl.merge(L5coll.map(getband('L5',bandname)));

LandsatColl = LandsatColl.merge(L4coll.map(getband('L4',bandname)));

var TimeSeries = ui.Chart.image.series(

   LandsatColl, geometry, ee.Reducer.mean(), 30, 'system:time_start')

       .setChartType('ScatterChart')

       .setOptions({

         vAxis: {title: bandname},

         lineWidth: 1,

         pointSize: 4

});

print(TimeSeries)

以下是运行结果