Google Earth Engine（GEE）——用10米分辨率土地分类数据进行土地面积计算出现错误

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发布于 2024-02-02 13:36:41

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发布于 2024-02-02 13:36:41

文章被收录于专栏：GEE数据专栏，GEE学习专栏，GEE错误集等专栏

错误：

FeatureCollection (Error)

Error in map(ID=0): Feature, argument 'geometry': Invalid type. Expected type: Geometry. Actual type: Feature.

原始代码：

var boten = ee.FeatureCollection("projects/ee-suraj7-28/assets/Boten");
var boten_shp = boten.geometry()
var Lunagprabang = ee.FeatureCollection("projects/ee-suraj7-28/assets/Luangprabang");
var Lunagprabang_shp = Lunagprabang.geometry()
var Vientiana = ee.FeatureCollection("projects/ee-suraj7-28/assets/Vientiana");
var Vientiana_shp = Vientiana.geometry()

// Buffer//
var boten_buffer=boten_shp.buffer(20000)
var Lunagprabang_buffer=Lunagprabang_shp.buffer(20000)
var Vientiana_buffer=Vientiana_shp.buffer(20000)


var features = ee.FeatureCollection([
  ee.Feature(boten_buffer, {label: 'Boten'}),
  ee.Feature(Lunagprabang_buffer, {label: 'Lunagprabang'}),
  ee.Feature(Vientiana_buffer, {label: 'vientiana'}),
])
print(features)

var years = ee.List.sequence(2021,2022)


var calculateClassAreaByYear = features.map(function(feature){
  var dw2=years.map(function(year){
  var dw1= ee.ImageCollection('GOOGLE/DYNAMICWORLD/V1')
              .filterDate(ee.Date.fromYMD(year, 1, 1), ee.Date.fromYMD(year, 12, 1)).filter(ee.Filter.bounds(feature)).select('label').reduce(ee.Reducer.mode()).eq(6);
              return dw1
              })
              return ee.FeatureCollection(dw2)
    })

print(calculateClassAreaByYear.flatten())

我们这里可以看到提示期待的类型不对，需求的类型是几何图形，但是这里给的确实矢量，所以我们需要再后面加一个.geometry()

修改后的代码：

var years = ee.List.sequence(2021,2022)


var calculateClassAreaByYear = features.map(function(feature){
  var dw2=years.map(function(year){
  var dw1= ee.ImageCollection('GOOGLE/DYNAMICWORLD/V1')
              .filterDate(ee.Date.fromYMD(year, 1, 1), ee.Date.fromYMD(year, 12, 31)).filter(ee.Filter.bounds(feature.geometry())).select('label').reduce(ee.Reducer.mode()).eq(6);
  var areaImage = dw1.multiply(ee.Image.pixelArea())    
  var area = areaImage.reduceRegion({
  reducer: ee.Reducer.sum(),
  geometry: feature.geometry(),
  scale: 10,
  maxPixels: 1e10
  })

这里有一个矢量面积的计算函数：

ee.Image.pixelArea() Generate an image in which the value of each pixel is the area of that pixel in square meters. The returned image has a single band called "area."

ee.Image.pixelArea() 生成一个图像，其中每个像素的值是该像素的面积，单位是平方米。返回的图像有一个称为 "面积 "的单带。

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原始发表：2022-08-18，如有侵权请联系 cloudcommunity@tencent.com 删除

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