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a846232e04
@ -1,173 +0,0 @@
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/**
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* Landsat 系列地表温度 (LST) 数据下载 —— 以年平均温度处理下载为例
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*
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* @author CVEO Team
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* @date 2026-01-15
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*
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* 1. 加载 Landsat-8, Landsat-9 SR 数据
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* 2. 合并 Landsat-8, Landsat-9 LST 数据
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* 3. 合成年度平均 Landsat LST 数据
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* 4. 导出 COG 云优化并填补缺失值的 GeoTIFF 影像 (大区域 GEE 自动分块下载)
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*/
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// 加载研究区域和影像
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var region_name = "应城市";
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var region_name_en = "Yingcheng";
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var region = Yingcheng;
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var crs = "EPSG:4526";
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// var region_name = "保康县";
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// var region_name_en = "Baokang";
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// var region = Baokang;
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// var crs = "EPSG:4525";
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var start_year = 2021;
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var end_year = 2025;
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var start_date = start_year + "-01-01";
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var end_date = end_year + "-12-31";
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var cloud_threshold = 90; // 最大云量阈值
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var LansatBands = ["ST_B10"];
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var commonBands = ["LST"];
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var region_geo = region.geometry();
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var bounds = region_geo.bounds();
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var common_filter = ee.Filter.and(
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ee.Filter.bounds(bounds),
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ee.Filter.date(start_date, end_date)
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);
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/**
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* Applies scaling factors.
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* @param {ee.Image} image Landsat SR image
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* @returns {ee.Image} Landsat SR image with scaled bands
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*/
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function applyScaleFactors(image) {
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var opticalBands = image.select("SR_B.").multiply(0.0000275).add(-0.2);
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var thermalBands = image.select("ST_B.*").multiply(0.00341802).add(149.0);
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return image
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.addBands(opticalBands, null, true)
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.addBands(thermalBands, null, true);
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}
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/**
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* 开尔文转摄氏度
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* @param {ee.Image} image Landsat LST image
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* @returns {ee.Image} Landsat LST image in Celsius
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*/
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function kelvinToCelsius(image) {
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return ee.Image(image.expression("B1 - 273.15", { B1: image.select(0) }))
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.rename("LST")
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.copyProperties(image)
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.copyProperties(image, ["system:time_start", "system:index", "system:id"]);
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}
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/**
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* Function to mask clouds using the Landsat QA_PIXEL and QA_RADSAT bands
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* @param {ee.Image} image Landsat SR image
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* @return {ee.Image} cloud masked and saturated Landsat SR image
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*/
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function maskLandsatclouds(image) {
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var qa = image.select("QA_PIXEL");
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var qa_radsat = image.select("QA_RADSAT");
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// Bits 3 and 4 are cloud and cloud shadow, respectively.
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var cloudBitMask = 1 << 3;
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var shadowBitMask = 1 << 4;
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// Both flags should be set to zero, indicating clear conditions.
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var mask = qa.bitwiseAnd(cloudBitMask).eq(0)
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.and(qa.bitwiseAnd(shadowBitMask).eq(0))
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.and(qa_radsat.eq(0));
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image = image.updateMask(mask);
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return image
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.copyProperties(image)
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.copyProperties(image, ["system:time_start", "system:index", "system:id"]);
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}
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// 加载 Landsat-8, Landsat-9 SR 数据
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var L8dataset = ee.ImageCollection("LANDSAT/LC08/C02/T1_L2")
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.filter(common_filter)
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.filter(ee.Filter.lt("CLOUD_COVER", cloud_threshold));
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print(start_date + " - " + end_date + " Landsat-8 SR dataset", L8dataset);
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var L9dataset = ee.ImageCollection("LANDSAT/LC09/C02/T1_L2")
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.filter(common_filter)
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.filter(ee.Filter.lt("CLOUD_COVER", cloud_threshold));
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print(start_date + " - " + end_date + " Landsat-9 SR dataset", L9dataset);
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// 合并 Landsat-8, Landsat-9 LST 数据
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var LSTdataset = L8dataset.merge(L9dataset)
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.map(applyScaleFactors)
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.map(maskLandsatclouds)
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.select(LansatBands, commonBands)
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.map(kelvinToCelsius);
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print(start_date + " - " + end_date + " Landsat-8,9 LST dataset", LSTdataset);
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// 合成年度平均 Landsat LST 数据
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var years = ee.List.sequence(start_year, end_year);
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var months = ee.List.sequence(1, 12);
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var yearlyLST = ee.ImageCollection.fromImages(
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years.map(function (y) {
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return ee.ImageCollection.fromImages(
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months.map(function (m) {
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return LSTdataset
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.filter(ee.Filter.calendarRange(y, y, "year"))
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.filter(ee.Filter.calendarRange(m, m, "month"))
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.mean()
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.clip(bounds)
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.set("month", m)
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.set("year", y);
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})
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).mean().set("year", y);
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})
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);
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if (start_year == end_year) {
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var year_str = start_year;
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} else {
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var year_str = start_year + "-" + end_year;
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}
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print(year_str + " Annual Mean Landsat LST dataset", yearlyLST);
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var total_mean_LST = LSTdataset.select("LST").mean();
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print(year_str + " Total Year Mean Landsat LST Histogram", ui.Chart.image.histogram(total_mean_LST, region, 100, 258));
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var annual_mean_LST = yearlyLST.select("LST").mean();
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print(year_str + " Annual Mean Landsat LST Histogram", ui.Chart.image.histogram(annual_mean_LST, region, 100, 258));
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var lst_vis = {
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min: 2,
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max: 40,
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palette: [
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'040274', '040281', '0502a3', '0502b8', '0502ce', '0502e6',
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'0602ff', '235cb1', '307ef3', '269db1', '30c8e2', '32d3ef',
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'3be285', '3ff38f', '86e26f', '3ae237', 'b5e22e', 'd6e21f',
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'fff705', 'ffd611', 'ffb613', 'ff8b13', 'ff6e08', 'ff500d',
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'ff0000', 'de0101', 'c21301', 'a71001', '911003'
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],
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};
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var styling = {
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color: "blue",
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fillColor: "00000000",
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};
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Map.centerObject(region, 10);
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Map.addLayer(total_mean_LST, lst_vis, year_str + " Landsat Total Year Mean LST");
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Map.addLayer(annual_mean_LST, lst_vis, year_str + " Landsat Annual Mean LST");
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Map.addLayer(region.style(styling), {}, region_name);
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// 导出合并后的影像
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// 明确设置数据类型为Float32, 否则默认类型为Float64, 会占用更多内存
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// 并对缺失值进行填充, 否则默认为nan不便于后续本地处理
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var processed_img = annual_mean_LST.toFloat().unmask(-9999.0);
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print("Start exporting " + year_str + "Yearly Mean LST image (" + crs + ")", processed_img);
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Export.image.toDrive({
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image: processed_img,
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description: region_name_en + "_LST_" + year_str,
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folder: "LST",
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region: region, // 添加后会自动裁剪
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scale: 30,
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crs: crs,
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maxPixels: 1e13, // GEE 最多支持 1e8 像素, 当超过时会自动分块
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fileFormat: "GeoTIFF",
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// 导出COG云优化的GeoTIFF影像, 并明确设置缺失值为-9999.0
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formatOptions: {
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cloudOptimized: true,
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noData: -9999.0,
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},
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});
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@ -1,267 +0,0 @@
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/**
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* 土地覆盖分类数据下载
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*
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* @author CVEO Team
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* @date 2025-10-27
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*
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* 1. 加载 ESA WorldCover, Dynamic World 等公开土地覆盖数据
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* - ESA WorldCover 2021 V200 版本: 11 类地物
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* - Dynamic World V1 版本: 9 类地物
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* 2. 加载 Sentinel-2 数据
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* 3. 导出 COG 云优化并填补缺失值的 GeoTIFF 影像 (大区域 GEE 自动分块下载)
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*/
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// 加载研究区域和影像
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// var region_name = "武汉市";
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// var region_name_en = "Wuhan";
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// var region = allCites.filter(ee.Filter.eq("市", region_name));
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var region_name = "49REL";
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var region_name_en = region_name;
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var region = grid;
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var year = 2025;
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var start_date = year + "-01-01";
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var end_date = year + "-12-31";
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var target_month = 5; // 指定月份
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var cloud_threshold = 60;
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// Use 'cs' or 'cs_cdf', depending on your use case; see docs for guidance.
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var QA_BAND = "cs_cdf";
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// The threshold for masking; values between 0.50 and 0.65 generally work well.
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// Higher values will remove thin clouds, haze & cirrus shadows.
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var CLEAR_THRESHOLD = 0.7;
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// Sentinel-2的B8A波段(20m)可能更适合代表近红外波段
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// var s2Bands = ["B2", "B3", "B4", "B8", "B11", "B12"];
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var s2Bands = ["B2", "B3", "B4", "B8A", "B11", "B12"];
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var commonBands = ["Blue", "Green", "Red", "NIR", "SWIR1", "SWIR2"];
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var bounds = region.geometry().bounds();
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var common_filter = ee.Filter.and(
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ee.Filter.bounds(bounds),
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ee.Filter.date(start_date, end_date)
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);
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/**
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* 基于 Cloud Score+ 云掩膜
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* @param {ee.Image} image Sentinel-2 image
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* @return {ee.Image} cloud masked Sentinel-2 image
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*/
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function maskS2cloudsByCS(image) {
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var cloudMask = image.select(QA_BAND).gte(CLEAR_THRESHOLD);
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image = image.updateMask(cloudMask);
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return image
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.copyProperties(image)
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.copyProperties(image, ["system:time_start", "system:index", "system:id"]);
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}
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/**
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* 按照属性值对影像集合进行排序
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* @param {ee.ImageCollection} collection 影像集合
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* @param {ee.Geometry} region 目标区域
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* @return {ee.ImageCollection} 排序后的影像集合
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*/
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function sortedByPriority(collection, region) {
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// 1. 计算每张影像的有效像素 (非空像素) 覆盖面积
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var withArea = collection.map(function (image) {
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var area = image
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.mask()
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.reduceRegion({
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reducer: ee.Reducer.sum(),
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geometry: region,
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scale: 10,
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maxPixels: 1e9,
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})
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.values()
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.get(0);
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return image.set("coverage_area", area);
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});
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// 2. 剔除覆盖面积为 0 的影像
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withArea = withArea.filter(ee.Filter.gt("coverage_area", 0));
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// 3. 根据云量 (降序) 和覆盖率 (升序) 对影像进行综合排序
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// 考虑影像集合是以栈的形式 (先入后出) 组织的, 在进行 mosaic 合成时, 从最后一张影像开始合并, 逆转排序
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// sort 默认升序 True
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var sorted = withArea
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.sort("CLOUDY_PIXEL_PERCENTAGE", false)
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.sort("coverage_area");
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return ee.ImageCollection(sorted);
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}
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// 加载Sentinel-2 L2A数据
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// Cloud Score+ image collection.
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// Note Cloud Score+ is produced from Sentinel-2 level 1C data and can be applied to either L1C or L2A collections.
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var S2csPlus = ee.ImageCollection("GOOGLE/CLOUD_SCORE_PLUS/V1/S2_HARMONIZED");
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var S2dataset = ee
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.ImageCollection("COPERNICUS/S2_SR_HARMONIZED")
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.filter(common_filter)
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.filter(ee.Filter.lt("CLOUDY_PIXEL_PERCENTAGE", cloud_threshold))
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.select(s2Bands, commonBands)
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.linkCollection(S2csPlus, [QA_BAND])
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.map(maskS2cloudsByCS);
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var target_s2 = sortedByPriority(
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S2dataset.filter(
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ee.Filter.calendarRange(target_month, target_month, "month")
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),
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region
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);
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var s2_img = ee.Image(target_s2.median());
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// 加载ESA WorldCover数据
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var ESA_worldcover = ee.ImageCollection("ESA/WorldCover/v200").first();
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var wc_img = ee.Image(ESA_worldcover.clip(region));
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var wc_class_names = {
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"Tree cover": 10,
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Shrubland: 20,
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Grassland: 30,
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Cropland: 40,
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"Built-up": 50,
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"Bare / sparse vegetation": 60,
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"Snow and ice": 70,
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"Permanent water bodies": 80,
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"Herbaceous wetland": 90,
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Mangroves: 95,
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"Moss and lichen": 100,
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};
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// 统计各类别覆盖面积
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var wc_class_area = wc_img
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.reduceRegion({
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reducer: ee.Reducer.frequencyHistogram(),
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geometry: region,
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scale: 10,
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maxPixels: 1e13,
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})
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.get("Map");
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print("ESA WorldCover 2021 v200");
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print("各类别名称:", wc_class_names);
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print("各类别覆盖面积:", wc_class_area);
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||||||
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// 加载Dynamic World数据
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var DWdataset = ee
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.ImageCollection("GOOGLE/DYNAMICWORLD/V1")
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.filter(common_filter)
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.select("label");
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||||||
// mode() 取出现次数最多的类别作为合成后的类别
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||||||
var dw_img = ee.Image(DWdataset.mode().clip(region));
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var dw_class_names = {
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||||||
water: 0,
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||||||
trees: 1,
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||||||
grass: 2,
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|
||||||
flooded_vegetation: 3,
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||||||
crops: 4,
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||||||
shrub_and_scrub: 5,
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||||||
built: 6,
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||||||
bare: 7,
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||||||
snow_and_ice: 8,
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||||||
};
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||||||
var built_img = dw_img.updateMask(dw_img.eq(dw_class_names.built));
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|
||||||
var crop_img = dw_img.updateMask(dw_img.eq(dw_class_names.crops));
|
|
||||||
var flood_img = dw_img.updateMask(dw_img.eq(dw_class_names.flooded_vegetation));
|
|
||||||
// 统计各类别覆盖面积
|
|
||||||
var dw_class_area = dw_img
|
|
||||||
.reduceRegion({
|
|
||||||
reducer: ee.Reducer.frequencyHistogram(),
|
|
||||||
geometry: region,
|
|
||||||
scale: 10,
|
|
||||||
maxPixels: 1e13,
|
|
||||||
})
|
|
||||||
.get("label");
|
|
||||||
print("Dynamic World v1");
|
|
||||||
print("各类别名称:", dw_class_names);
|
|
||||||
print("各类别覆盖面积:", dw_class_area);
|
|
||||||
|
|
||||||
var VIS_PALETTE = [
|
|
||||||
"419bdf",
|
|
||||||
"397d49",
|
|
||||||
"88b053",
|
|
||||||
"7a87c6",
|
|
||||||
"e49635",
|
|
||||||
"dfc35a",
|
|
||||||
"c4281b",
|
|
||||||
"a59b8f",
|
|
||||||
"b39fe1",
|
|
||||||
];
|
|
||||||
var DW_vis = {
|
|
||||||
min: 0,
|
|
||||||
max: 8,
|
|
||||||
palette: VIS_PALETTE,
|
|
||||||
};
|
|
||||||
|
|
||||||
var true_rgb_vis = {
|
|
||||||
bands: ["Red", "Green", "Blue"],
|
|
||||||
min: 0.0,
|
|
||||||
max: 3000,
|
|
||||||
};
|
|
||||||
|
|
||||||
var false_rgb_vis = {
|
|
||||||
min: 0.0,
|
|
||||||
max: 4000,
|
|
||||||
gamma: 1.4,
|
|
||||||
bands: ["NIR", "Red", "Green"],
|
|
||||||
};
|
|
||||||
|
|
||||||
var styling = {
|
|
||||||
color: "red",
|
|
||||||
fillColor: "00000000",
|
|
||||||
};
|
|
||||||
|
|
||||||
var WC_vis = {
|
|
||||||
bands: ["Map"],
|
|
||||||
};
|
|
||||||
|
|
||||||
Map.centerObject(region, 9);
|
|
||||||
Map.addLayer(region.style(styling), {}, region_name);
|
|
||||||
Map.addLayer(wc_img, WC_vis, "ESA 2021 Landcover");
|
|
||||||
Map.addLayer(dw_img, DW_vis, "Dynamic World LULC");
|
|
||||||
Map.addLayer(
|
|
||||||
s2_img,
|
|
||||||
true_rgb_vis,
|
|
||||||
year + "-" + target_month + " Sentinel-2 True RGB",
|
|
||||||
false
|
|
||||||
);
|
|
||||||
Map.addLayer(
|
|
||||||
s2_img,
|
|
||||||
false_rgb_vis,
|
|
||||||
year + "-" + target_month + " Sentinel-2 False RGB",
|
|
||||||
false
|
|
||||||
);
|
|
||||||
// Map.addLayer(built_img, DW_vis, 'Built DW LULC');
|
|
||||||
// Map.addLayer(crop_img, DW_vis, "Crop DW LULC");
|
|
||||||
// Map.addLayer(flood_img, DW_vis, "Flood DW LULC");
|
|
||||||
|
|
||||||
// 导出裁剪处理后的土地覆盖数据
|
|
||||||
var fileName = region_name_en + "_ESA_WorldCover_2021_v200";
|
|
||||||
// 区域过大, 需要先将 wc_img 划分为四块网格分开下载
|
|
||||||
var bounds = region.geometry().bounds();
|
|
||||||
var coords = ee.List(bounds.coordinates().get(0));
|
|
||||||
|
|
||||||
var minX = ee.Number(ee.List(coords.get(0)).get(0));
|
|
||||||
var minY = ee.Number(ee.List(coords.get(0)).get(1));
|
|
||||||
var maxX = ee.Number(ee.List(coords.get(2)).get(0));
|
|
||||||
var maxY = ee.Number(ee.List(coords.get(2)).get(1));
|
|
||||||
|
|
||||||
var midX = minX.add(maxX).divide(2);
|
|
||||||
var midY = minY.add(maxY).divide(2);
|
|
||||||
|
|
||||||
var grid1 = ee.Geometry.Rectangle([minX, minY, midX, midY]);
|
|
||||||
var grid2 = ee.Geometry.Rectangle([midX, minY, maxX, midY]);
|
|
||||||
var grid3 = ee.Geometry.Rectangle([minX, midY, midX, maxY]);
|
|
||||||
var grid4 = ee.Geometry.Rectangle([midX, midY, maxX, maxY]);
|
|
||||||
|
|
||||||
var grids = [grid1, grid2, grid3, grid4];
|
|
||||||
|
|
||||||
for (var i = 0; i < grids.length; i++) {
|
|
||||||
var grid_region = grids[i];
|
|
||||||
var clipped_img = wc_img.clip(grid_region);
|
|
||||||
var grid_fileName = fileName + "_grid_" + (i + 1);
|
|
||||||
Export.image.toDrive({
|
|
||||||
image: clipped_img,
|
|
||||||
description: grid_fileName,
|
|
||||||
folder: "LULC",
|
|
||||||
region: grid_region,
|
|
||||||
scale: 10,
|
|
||||||
maxPixels: 1e13, // GEE 最多支持 1e8 像素, 当超过时会自动分块
|
|
||||||
fileFormat: "GeoTIFF",
|
|
||||||
// 导出COG云优化的GeoTIFF影像
|
|
||||||
formatOptions: {
|
|
||||||
cloudOptimized: true,
|
|
||||||
},
|
|
||||||
});
|
|
||||||
}
|
|
||||||
Loading…
x
Reference in New Issue
Block a user