在 GEE Python API 中的 inner.Join 函数中使用过滤函数

Question

我需要在两个 MODIS 集合中应用过滤功能以按日期查找常见图像，但我不知道如何在 Python API 中执行此操作。我有这个错误：

EEException: Can not encode object: set (['system: time_start'])

GEE function:
    var filterTimeEq = ee.Filter.equals({
    leftField: 'system:time_start',
    rightField: 'system:time_start'
    });

GEE function in Python API:
    leftField = 'system:time_start'
    rightField = 'system:time_start'
    filterTimeEq = ee.Filter.equals({leftField, rightField})

Python API Code:
    terra = ee.ImageCollection('MODIS/006/MOD10A1').filterBounds(pt).select('NDSI_Snow_Cover').sort('system:time_start').filterDate('2016-01-01', '2017-12-31')
    aqua = ee.ImageCollection('MODIS/006/MYD10A1').filterBounds(pt).select('NDSI_Snow_Cover').sort('system:time_start').filterDate('2016-01-01', '2017-12-31')
    innerJoin = ee.Join.inner()
    innerJoinedCollection = innerJoin.apply(terra, aqua, filterTimeEq)
    joinedCollection = innerJoinedCollection.map(concatBands)
    yearlyCollection = joinedCollection.map(maxVal)
    start = ee.Date(yearlyCollection.first().get('system:time_start'))
    maxCollection=ee.ImageCollection(yearlyCollection)
    SnowCount = maxCollection.map(snowMask)

Answer 1

假设您的 concatbands 函数是这样定义的：

def concatBands(image): 
    return ee.Image.cat(image.get('primary'),image.get('secondary'))

在python中，filtertimeEq应该写成：

filterTimeEq = ee.Filter.equals(leftField = 'system:time_start',rightField = 'system:time_start')

在 GEE Python API 中的 inner.Join 函数中使用过滤函数

Using a filter function in a inner.Join function in GEE Python API

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