如何解决缩小图像集合的Google Earth Engine
我正在使用CHIRPS数据集(每日降水)来导出特定时间范围内的平均,中位数,最小和最大降水。然后,我要提取点shapefile中包含的特定位置的值,并将结果保存在表中。 该脚本似乎可以工作,但是输出表中只有零(0)作为4个变量的值。 请参见下面的脚本var lng = 65.64;
var lat = 34.35;
var point = ee.Geometry.Point(lat,lng);
//var aoi = point.buffer(100000); // Create an area (1km buffer around point)
var country = ee.FeatureCollection('USDOS/LSIB_SIMPLE/2017')
.filter(ee.Filter.eq('country_co','AF'));
var aoi = country;
Map.setCenter(lng,lat,5); // Center the map on this location,zoom level 10
var start = '2018-02-15'; // initial date of the image collection
var end = '2018-07-15'; //final date of the image collection
var p1 = ee.Geometry.Point([69.78086,34.65411])
var p2 = ee.Geometry.Point([61.82234,30.66048])
var table = ee.FeatureCollection(ee.List([ee.Feature(p1),ee.Feature(p2)]))
var AddPrMean = function(image) {
var PrMean = image.reduce(ee.Reducer.mean()).rename('PrMean');
return image.addBands(PrMean);
};
var AddPrMedian = function(image) {
var PrMedian = image.reduce(ee.Reducer.median()).rename('PrMedian');
return image.addBands(PrMedian);
};
var AddPrMin = function(image) {
var PrMin = image.reduce(ee.Reducer.min()).rename('PrMin');
return image.addBands(PrMin);
};
var AddPrMax = function(image) {
var PrMax = image.reduce(ee.Reducer.max()).rename('PrMax');
return image.addBands(PrMax);
};
var dataset = ee.ImageCollection('UCSB-CHG/CHIRPS/DAILY')
.filterDate(start,end)
.filterBounds(aoi)
.map(AddPrMean)
.map(AddPrMedian)
.map(AddPrMin)
.map(AddPrMax);
var composites = dataset.select(['PrMean','PrMedian','PrMin','PrMax']).first();
var YieldLocations = ee.FeatureCollection(table);
var YPrec = composites.reduceRegions(YieldLocations,ee.Reducer.max(),1);
print(YPrec); ```
解决方法
我找到了一个似乎可行的解决方案,但是中位数始终为0。
var lat = 34.35;
var point = ee.Geometry.Point(lat,lng);
//var aoi = point.buffer(100000); // Create an area (1km buffer around point)
var country = ee.FeatureCollection('USDOS/LSIB_SIMPLE/2017')
.filter(ee.Filter.eq('country_co','AF'));
var aoi = country;
Map.setCenter(lng,lat,5); // Center the map on this location,zoom level 10
var start = '2018-02-15'; // initial date of the image collection
var end = '2018-07-15'; //final date of the image collection
var p1 = ee.Geometry.Point([69.78086,34.65411])
var p2 = ee.Geometry.Point([61.82234,30.66048])
var table = ee.FeatureCollection(ee.List([ee.Feature(p1),ee.Feature(p2)]))
var dataset = ee.ImageCollection('UCSB-CHG/CHIRPS/DAILY')
.filterDate(start,end)
.filterBounds(aoi);
var PrMean = dataset.mean().rename('PrMean');
var PrMedian = dataset.median().rename('PrMedian');
var PrMin = dataset.min().rename('PrMin');
var PrMax = dataset.max().rename('PrMax');
var composites = PrMean
.addBands(PrMedian)
.addBands(PrMin)
.addBands(PrMax);
var YieldLocations = ee.FeatureCollection(table);
var YPrec = composites.reduceRegions(YieldLocations,ee.Reducer.max(),1);
print(YPrec);```
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