# xarray.Dataset.coarsen

#### Dataset.coarsen(dim=None, boundary='exact', side='left', coord_func='mean', \*\*window_kwargs)[[source]](https://github.com/pydata/xarray/blob/main/xarray/core/dataset.py#L10654-L10706)

Coarsen object for Datasets.

* **Parameters:**
  * **dim** ([mapping](https://docs.python.org/3/glossary.html#term-mapping) of [hashable](../user-guide/terminology.html.md#term-name) to [`int`](https://docs.python.org/3/builtins/functions.html#int), *optional*) – Mapping from the dimension name to the window size.
  * **boundary** (`{"exact", "trim", "pad"}`, *default*: `"exact"`) – If ‘exact’, a ValueError will be raised if dimension size is not a
    multiple of the window size. If ‘trim’, the excess entries are
    dropped. If ‘pad’, NA will be padded.
  * **side** (`{"left", "right"}` or [mapping](https://docs.python.org/3/glossary.html#term-mapping) of [`str`](https://docs.python.org/3/builtins/stdtypes.html#str) to `{"left", "right"}`, *default*: `"left"`)
  * **coord_func** ([`str`](https://docs.python.org/3/builtins/stdtypes.html#str) or [mapping](https://docs.python.org/3/glossary.html#term-mapping) of [hashable](../user-guide/terminology.html.md#term-name) to [`str`](https://docs.python.org/3/builtins/stdtypes.html#str), *default*: `"mean"`) – function (name) that is applied to the coordinates,
    or a mapping from coordinate name to function (name).
* **Returns:**
  [`computation.rolling.DatasetCoarsen`](xarray.computation.rolling.DatasetCoarsen.html.md#xarray.computation.rolling.DatasetCoarsen)

#### SEE ALSO
[`computation.rolling.DatasetCoarsen`](xarray.computation.rolling.DatasetCoarsen.html.md#xarray.computation.rolling.DatasetCoarsen)
[`DataArray.coarsen`](xarray.DataArray.coarsen.html.md#xarray.DataArray.coarsen)

[Reshaping via coarsen](../user-guide/reshaping.html.md#reshape-coarsen)
: User guide describing [`coarsen()`](#xarray.Dataset.coarsen)

[Coarsen large arrays](../user-guide/computation.html.md#compute-coarsen)
: User guide on block aggregation [`coarsen()`](#xarray.Dataset.coarsen)

[Windowed Computations](https://tutorial.xarray.dev/fundamentals/03.3_windowed.html)
: Tutorial on windowed computation using [`coarsen()`](#xarray.Dataset.coarsen)