feat: n_images_per_interval prop on reduceInterval

geetools/ee_image_collection.py

@@ -957,7 +957,7 @@ def aggregateArray(self, properties: list[str] | ee.List | None = None) -> ee.Di
         values = keys.map(lambda p: self._obj.aggregate_array(p))
         return ee.Dictionary.fromLists(keys, values)
 
-    def groupInterval(self, unit: str = "month", duration: int = 1) -> ee.List:
+    def groupInterval(self, unit: str = "month", duration: int = 1, count_images_per_interval: bool = False) -> ee.List:
         """Transform the :py:class:`ee.ImageCollection` into a list of smaller collection of the specified duration.
 
         For example using unit as "month" and duration as 1, the :py:class:`ee.ImageCollection` will be transformed
@@ -968,6 +968,7 @@ def groupInterval(self, unit: str = "month", duration: int = 1) -> ee.List:
         Args:
             unit: The unit of time to split the collection. Available units: ``year``, ``month``, ``week``, ``day``, ``hour``, ``minute`` or ``second``.
             duration: The duration of each split.
+            count_images_per_interval: Whether to add the property `n_images_per_interval` with the number of images used for the reduction in each interval.
 
         Returns:
             A list of :py:class:`ee.ImageCollection` grouped by interval
@@ -988,7 +989,7 @@ def groupInterval(self, unit: str = "month", duration: int = 1) -> ee.List:
                 split = collection.geetools.groupInterval("month", 1)
                 print(split.getInfo())
         """
-        sizeName = "__geetools_generated_size__"  # set generated properties name
+        sizeName = "n_images_per_interval"  # set generated properties name
 
         # create an ic variable to avoid calling self._obj multiple times
         # and extract the property names to copy
@@ -1011,10 +1012,11 @@ def add_size(ic):
         def delete_size_property(ic):
             ic = ee.ImageCollection(ic)
             return ee.ImageCollection(ic.copyProperties(ic, properties=toCopy))
+
+        imageCollectionList = imageCollectionList.map(add_size).filter(ee.Filter.gt(sizeName, 0))
 
-        imageCollectionList = (
-            imageCollectionList.map(add_size).filter(ee.Filter.gt(sizeName, 0)).map(delete_size_property)
-        )
+        if not count_images_per_interval:
+            imageCollectionList = imageCollectionList.map(delete_size_property)
 
         return ee.List(imageCollectionList)
 
@@ -1024,6 +1026,7 @@ def reduceInterval(
         unit: str = "month",
         duration: int = 1,
         keep_original_names: bool = True,
+        count_images_per_interval: bool = False,
     ) -> ee.ImageCollection:
         """Reduce the images included in the same duration interval using the provided reducer.
 
@@ -1037,6 +1040,7 @@ def reduceInterval(
             unit: The unit of time to split the collection. Available units: ``year``, ``month``, ``week``, ``day``, ``hour``, ``minute`` or ``second``.
             duration: The duration of each split.
             keep_original_names: Whether to keep the original band names or not. This is a workaround to preserve older behaviour, it should disappear in the future.
+            count_images_per_interval: Whether to add the property `n_images_per_interval` with the number of images used for the reduction in each interval.
 
         Returns:
             A new :py:class:`ee.ImageCollection` with the reduced images.
@@ -1059,7 +1063,7 @@ def reduceInterval(
         """
         # create a list of image collections to be reduced
         # Every subcollection is sorted in case one use the "first" reducer
-        imageCollectionList = self.groupInterval(unit, duration)
+        imageCollectionList = self.groupInterval(unit, duration, count_images_per_interval)
 
         # create a reducer from user parameters
         red = getattr(ee.Reducer, reducer)() if isinstance(reducer, str) else reducer

tests/test_ImageCollection.py

@@ -373,6 +373,25 @@ def test_reduce_interval_image_with_system_id(self, s2_sr):
         firstImg = ic.first()
         assert "system:id" in firstImg.propertyNames().getInfo()
 
+    def test_reduce_interval_with_count_images_per_interval(self, jaxa_rainfall):
+        # get 3 month worth of data and group it with default parameters
+        ic = jaxa_rainfall.filterDate("2020-01-01", "2020-01-02")
+        reduced = ic.geetools.reduceInterval("mean", duration=1, unit="day", count_images_per_interval=True)
+        firstImg = reduced.first()
+        assert "n_images_per_interval" in firstImg.propertyNames().getInfo()
+
+    def test_reduce_interval_with_count_images_per_interval_count(self, jaxa_rainfall):
+        ic = jaxa_rainfall.filterDate("2020-01-01", "2020-01-02")
+        reduced = ic.geetools.reduceInterval("mean", duration=1, unit="day", count_images_per_interval=True)
+        firstImg = reduced.first()
+        assert firstImg.get('n_images_per_interval').getInfo() == 24
+
+    def test_reduce_interval_with_count_images_per_interval_empty_days(self, s2_sr):
+        ic = s2_sr.filterDate("2021-01-01", "2021-01-07")
+        reduced = ic.geetools.reduceInterval("mean", duration=1, unit="day", count_images_per_interval=True)
+        count_images_per_interval = reduced.aggregate_array("n_images_per_interval").getInfo()
+        assert count_images_per_interval == [0, 1, 0]
+
 
 class TestClosestDate:
     """Test the ``closestDate`` method."""