尝试从JavaScript到RGEE的转换

Question

我试图将这段代码从EarthEngine (JavaScript)重写到RGEE：

function collection_index(image) {
  
  function setNdviMinMax(img) {
    var minMax = img
    .select('NDVI')
    .reduceRegion({
      reducer: ee.Reducer.minMax(),
      scale: 20,
      maxPixels: 1e13
    });
  return img.set({
    'NDVI_min': minMax.get('NDVI_min'),
    'NDVI_max': minMax.get('NDVI_max'),
  });
  }  
  
  var ndvi_param = image.normalizedDifference(['B8', 'B4']);
  ndvi_param =  ndvi_param.rename('NDVI');
  var SWIR_param = image.select('B12').rename('SWIR').divide(10000);
  var STR_param = SWIR_param.expression(
  '((1-SWIR)**2)/(2*SWIR)',{
    'SWIR' : SWIR.select('SWIR'),
  }).rename('STR')
  
  ndvi_param = setNdviMinMax(ndvi_param)
  
  
  ndvi_param = ndvi_param.updateMask(agrico)
 
  return ndvi_param.addBands(STR_param) 
}

var coll = S2.map(collection_index)

print(coll)

我就这样做了：

collection_index <- function(image){
  setNdviMinMax <- function(img){
    minMax <- img$select('NDVI')$
      reduceRegion(list(reducer= ee$Reducer$minMax(),
                        scale= 20,
                        maxPixels = 1e+09)
      )
    return(img$set(
      list(
        'NDVI_min'= minMax$get('NDVI_min'),
        'NDVI_max'= minMax$get('NDVI_max')
      )
    )
      
    )
  }
  ndvi_param <- image$normalizedDifference(list("B8", "B3"))
  ndvi_param <-  ndvi_param$rename('NDVI')
  SWIR_param <- image$select('B12')$rename('SWIR')$divide(10000)
  STR_param <- SWIR_param$expression('((1-SWIR)**2)/(2*SWIR)', list('SWIR' = SWIR$select('SWIR')))$rename('STR')
  ndvi_param <- setNdviMinMax(ndvi_param)
  ndvi_param <- ndvi_param$updateMask(agrico)
return(ndvi_param$addBands(STR_param) )
}

coll <- S2$map(collection_index)
ee_print(coll)

但是，我有以下错误：

py_call_impl中的错误(可调用的，点$args，点$关键字)：RuntimeError:计算错误: ee.ee_exception.EEException: ee.Reducer()的无效参数：({‘还原者’：0x7fd1e3548220>上的

有人能帮我解决这个错误吗？

非常感谢

https://code.earthengine.google.com/42db584622de1309c60faf4cb5f88573

Answer 1

我不知道R，所以这完全是基于看别人的例子，但我确信错误在这里：

      reduceRegion(list(reducer= ee$Reducer$minMax(),
                        scale= 20,
                        maxPixels = 1e+09)
      )

reduceRegion使用的不是字典，而是命名参数。所以这应该是

      reduceRegion(
        reducer = ee$Reducer$minMax(),
        scale = 20,
        maxPixels = 1e+09
      )