十五

var join2 = ee.Join.saveAll({

matchesKey: \''before\'',

ordering: \''system:time_start\'',

ascending: true})

var join2Result = join2.apply({

primary: join1Result,

secondary: join1Result,

condition: filter2

})

//第四步：利用线性插值先把空数据插出来。

var filtered = join2Result.filter(ee.Filter.eq(\''type\'', \''interpolated\''))

//定义插值函数

function interpolateImages(image) {

var image = ee.Image(image)

var beforeImages = ee.List(image.get(\''before\''))

var beforeMosaic = ee.ImageCollection.fromImages(beforeImages).mosaic()

var afterImages = ee.List(image.get(\''after\''))

var afterMosaic = ee.ImageCollection.fromImages(afterImages).mosaic()

var t1 = beforeMosaic.select(\''timestamp\'').rename(\''t1\'')

var t2 = afterMosaic.select(\''timestamp\'').rename(\''t2\'')

var t = image.metadata(\''system:time_start\'').rename(\''t\'')

var timeImage = ee.Image.cat([t1, t2, t])

var timeRatio = timeImage.expression(\''(t - t1) / (t2 - t1)\'', {

\''t\'': timeImage.select(\''t\''),

\''t1\'': timeImage.select(\''t1\''),

\''t2\'': timeImage.select(\''t2\''),

})

var interpolated = beforeMosaic

.add((afterMosaic.subtract(beforeMosaic).multiply(timeRatio)))

var result = image.unmask(interpolated)

return result.copyProperties(image, [\''system:time_start\''])

}

//进行时间插值，选择插值后的ndvi数据集，生成时间序列

var interpolatedCol = ee.ImageCollection(

filtered.map(interpolateImages)).select(\''ndvi\'');

var regularCol = interpolatedCol.filter(ee.Filter.eq(\''type\'', \''interpolated\''));

var interCol=regularCol.select(\''ndvi\'');

var chart = ui.Chart.image.series({

imageCollection: regularCol.select(\''ndvi\''),

region: geometry,

reducer: ee.Reducer.mean(),

scale: 20

}).setOptions({

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