# Example licensed under cc by-sa 3.0 with attribution required

from contextlib import contextmanager

import rasterio
from rasterio import Affine, MemoryFile
from rasterio.enums import Resampling

# use context manager so DatasetReader and MemoryFile get cleaned up automatically
@contextmanager
def resample_raster(raster, scale=2):
    t = raster.transform

    # rescale the metadata
    transform = Affine(t.a / scale, t.b, t.c, t.d, t.e / scale, t.f)
    height = raster.height * scale
    width = raster.width * scale

    profile = src.profile
    profile.update(transform=transform, driver='GTiff', height=height, width=width)

    data = raster.read( # Note changed order of indexes, arrays are band, row, col order not row, col, band
            out_shape=(raster.count, height, width),
            resampling=Resampling.bilinear,
        )

    with MemoryFile() as memfile:
        with memfile.open(**profile) as dataset: # Open as DatasetWriter
            dataset.write(data)
            del data

        with memfile.open() as dataset:  # Reopen as DatasetReader
            yield dataset  # Note yield not return


with rasterio.open('path/to/raster') as src:
    with resample_raster(src) as resampled:
        print('Orig dims: {}, New dims: {}'.format(src.shape, resampled.shape))
        print(repr(resampled))