feat(GEE_Scripts): 添加Sentinel-1影像下载脚本.

GEE_Scripts/Sentinel-1_download.js

@@ -0,0 +1,74 @@
+/**
+ * Sentinel-1 哨兵一号数据下载 —— 以下载 2023-2024 年云南省边境影像为例
+ *
+ * @author CVEO Team
+ * @date 2025-12-18
+ *
+ * 1. 加载 Sentinel-1 数据
+ * 2. 导出COG云优化并填补缺失值的GeoTIFF影像分块
+ */
+
+// 加载研究区域和影像
+// var region_name = "德宏傣族景颇族自治州"; // 瑞丽县所在
+var region_name = "保山市"; // 德宏州东侧
+var region_name_en = "baoshan";
+var region = allCites.filter(ee.Filter.eq("市", region_name));
+var yunnan = allCites.filter(ee.Filter.eq("省", "云南省"));
+var year = 2023;
+var start_date = year + "-04-09";
+var end_date = year + "-04-11";
+var region_geo = region.geometry();
+var bounds = region_geo.bounds();
+var common_filter = ee.Filter.and(
+  ee.Filter.bounds(bounds),
+  ee.Filter.date(start_date, end_date)
+);
+
+// 加载Sentinel-1 GRD数据
+var S1dataset = ee
+  .ImageCollection("COPERNICUS/S1_GRD")
+  .filter(common_filter)
+  .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VV'))
+  .filter(ee.Filter.eq('instrumentMode', 'IW'))
+  .select('VV');
+print(start_date + " - " + end_date + " S1dataset", S1dataset);
+var s1_img = ee.Image(S1dataset.median());
+
+var s1_vis = {
+  min: -25,
+  max: 5
+};
+
+var styling1 = {
+  color: "blue",
+  fillColor: "00000000",
+};
+
+var styling2 = {
+  color: "red",
+  fillColor: "00000000",
+};
+
+Map.centerObject(region, 7);
+Map.addLayer(s1_img, s1_vis, start_date + " Sentinel-1 GRD");
+Map.addLayer(yunnan.style(styling2), {}, "云南省");
+Map.addLayer(region.style(styling1), {}, region_name);
+
+// 导出 Sentinel-1 影像
+// 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
+// 并对缺失值进行填充, 否则默认为nan不便于后续本地处理
+var processed_img = S1dataset.first().toFloat().unmask(-9999.0);
+Export.image.toDrive({
+  image: processed_img,
+  description: "S1A_IW_GRDH_1SDV_" + start_date,
+  folder: "Sentinel-1",
+  // region: 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, 并明确设置缺失值为-9999.0
+  formatOptions: {
+    cloudOptimized: true,
+    noData: -9999.0,
+  },
+});