导出 Google Earth Engine 图像 collection 中的所有图像(Google Earth Engine API)
Exporting all images in a Google Earth Engine image collection (Google Earth Engine API)
我需要为我的论文下载一堆 Landsat 图像。我的问题看起来很简单,但我对 JavaScript 一无所知,文档也没有提供足够的帮助。
我已将 collection 过滤到我的地区和时间段,我想将所有图像分别导出到云端硬盘。
Collection 示例:
var surfaceReflectanceL5 = ee.ImageCollection('LANDSAT/LT5_SR');
var dateSR5=surfaceReflectanceL5.filterDate('1984-01-01', '1985-01-01');
var prSR5=dateSR5.filter(ee.Filter.eq('wrs_path', 182))
.filter(ee.Filter.eq('wrs_row', 35));
单张图片导出代码为:
Export.image.toDrive({
image: image1 //example, var image1='Landsat/....'
description: 'L51984_1',
scale: 30,
});
如何遍历 collection 以导出所有图像?使用 map() 函数似乎是答案。
prSR5.map(Export.image.toDrive({
image: image,
description: 'L51984',
scale: 30,
}));
问题是如何将图像参数设置为正确的图像(即首先是第 1 张图像,然后是第 2 张图像,诸如 'thisImage()
' 之类)以及匹配图像的描述(即 'L51984_1'
,'L51984_2'
...).
非常感谢!!!
我创建了一个函数来执行类似的操作。它在我创建的一堆 gee 工具中可用:https://github.com/fitoprincipe/geetools-code-editor
代码如下:
/*
* Author: Rodrigo E. Principe
* License: Apache 2.0
PURPOSE:
This function Exports all images from one Collection
PARAMETERS:
col = collection that contains the images (ImageCollection) (not optional)
folder = the folder where images will go (str) (not optional)
scale = the pixel's scale (int) (optional) (defaults to 1000) (for Landsat use 30)
type = data type of the exported image (str) (option: "float", "byte", "int", "double") (optional) (defaults to "float")
nimg = number of images of the collection (can be greater than the actual number) (int) (optional) (defaults to 500)
maxPixels = max number of pixels to include in the image (int) (optional) (defults to 1e10)
region = the region where images are on (Geometry.LinearRing or Geometry.Polygon) (optional) (defaults to the image footprint)
Be careful with the region parameter. If the collection has images
in different regions I suggest not to set that parameter
EXAMPLE:
ExportCol(myLandsatCol, "Landsat_imgs", 30)
*/
var ExportCol = function(col, folder, scale, type,
nimg, maxPixels, region) {
type = type || "float";
nimg = nimg || 500;
scale = scale || 1000;
maxPixels = maxPixels || 1e10;
var colList = col.toList(nimg);
var n = colList.size().getInfo();
for (var i = 0; i < n; i++) {
var img = ee.Image(colList.get(i));
var id = img.id().getInfo();
region = region || img.geometry().bounds().getInfo()["coordinates"];
var imgtype = {"float":img.toFloat(),
"byte":img.toByte(),
"int":img.toInt(),
"double":img.toDouble()
}
Export.image.toDrive({
image:imgtype[type],
description: id,
folder: folder,
fileNamePrefix: id,
region: region,
scale: scale,
maxPixels: maxPixels})
}
}
我没有尝试过很多,但在我做的几个测试中工作,例如:
var batch = require('users/fitoprincipe/geetools:batch')
var col = ee.ImageCollection("LEDAPS/LE7_L1T_SR").filterDate("2002-01-01","2002-01-03");
batch.Download.ImageCollection.toDrive(col, "Folder", {scale:30});
如果您有任何问题,可以在这里发表评论,也可以 post 在 github 上发表评论。
我需要为我的论文下载一堆 Landsat 图像。我的问题看起来很简单,但我对 JavaScript 一无所知,文档也没有提供足够的帮助。 我已将 collection 过滤到我的地区和时间段,我想将所有图像分别导出到云端硬盘。 Collection 示例:
var surfaceReflectanceL5 = ee.ImageCollection('LANDSAT/LT5_SR');
var dateSR5=surfaceReflectanceL5.filterDate('1984-01-01', '1985-01-01');
var prSR5=dateSR5.filter(ee.Filter.eq('wrs_path', 182))
.filter(ee.Filter.eq('wrs_row', 35));
单张图片导出代码为:
Export.image.toDrive({
image: image1 //example, var image1='Landsat/....'
description: 'L51984_1',
scale: 30,
});
如何遍历 collection 以导出所有图像?使用 map() 函数似乎是答案。
prSR5.map(Export.image.toDrive({
image: image,
description: 'L51984',
scale: 30,
}));
问题是如何将图像参数设置为正确的图像(即首先是第 1 张图像,然后是第 2 张图像,诸如 'thisImage()
' 之类)以及匹配图像的描述(即 'L51984_1'
,'L51984_2'
...).
非常感谢!!!
我创建了一个函数来执行类似的操作。它在我创建的一堆 gee 工具中可用:https://github.com/fitoprincipe/geetools-code-editor
代码如下:
/*
* Author: Rodrigo E. Principe
* License: Apache 2.0
PURPOSE:
This function Exports all images from one Collection
PARAMETERS:
col = collection that contains the images (ImageCollection) (not optional)
folder = the folder where images will go (str) (not optional)
scale = the pixel's scale (int) (optional) (defaults to 1000) (for Landsat use 30)
type = data type of the exported image (str) (option: "float", "byte", "int", "double") (optional) (defaults to "float")
nimg = number of images of the collection (can be greater than the actual number) (int) (optional) (defaults to 500)
maxPixels = max number of pixels to include in the image (int) (optional) (defults to 1e10)
region = the region where images are on (Geometry.LinearRing or Geometry.Polygon) (optional) (defaults to the image footprint)
Be careful with the region parameter. If the collection has images
in different regions I suggest not to set that parameter
EXAMPLE:
ExportCol(myLandsatCol, "Landsat_imgs", 30)
*/
var ExportCol = function(col, folder, scale, type,
nimg, maxPixels, region) {
type = type || "float";
nimg = nimg || 500;
scale = scale || 1000;
maxPixels = maxPixels || 1e10;
var colList = col.toList(nimg);
var n = colList.size().getInfo();
for (var i = 0; i < n; i++) {
var img = ee.Image(colList.get(i));
var id = img.id().getInfo();
region = region || img.geometry().bounds().getInfo()["coordinates"];
var imgtype = {"float":img.toFloat(),
"byte":img.toByte(),
"int":img.toInt(),
"double":img.toDouble()
}
Export.image.toDrive({
image:imgtype[type],
description: id,
folder: folder,
fileNamePrefix: id,
region: region,
scale: scale,
maxPixels: maxPixels})
}
}
我没有尝试过很多,但在我做的几个测试中工作,例如:
var batch = require('users/fitoprincipe/geetools:batch')
var col = ee.ImageCollection("LEDAPS/LE7_L1T_SR").filterDate("2002-01-01","2002-01-03");
batch.Download.ImageCollection.toDrive(col, "Folder", {scale:30});
如果您有任何问题,可以在这里发表评论,也可以 post 在 github 上发表评论。