block_reduce¶
- ccdproc.block_reduce(ccd, block_size, func=<function sum>)[source]¶
Thin wrapper around
astropy.nddata.block_reduce
. Downsample a data array by applying a function to local blocks.If
data
is not perfectly divisible byblock_size
along a given axis then the data will be trimmed (from the end) along that axis.- Parameters
- dataarray-like
The data to be resampled.
- block_sizeint or array-like (int)
The integer block size along each axis. If
block_size
is a scalar anddata
has more than one dimension, thenblock_size
will be used for for every axis.- funccallable, optional
The method to use to downsample the data. Must be a callable that takes in a
ndarray
along with anaxis
keyword, which defines the axis or axes along which the function is applied. Theaxis
keyword must accept multiple axes as a tuple. The default issum
, which provides block summation (and conserves the data sum).
- Returns
- outputarray-like
The resampled data.
Examples
>>> import numpy as np >>> from astropy.nddata import block_reduce >>> data = np.arange(16).reshape(4, 4) >>> block_reduce(data, 2) array([[10, 18], [42, 50]])
>>> block_reduce(data, 2, func=np.mean) array([[ 2.5, 4.5], [ 10.5, 12.5]])