Profiles and Writing Files

How to use profiles when opening files.

Like Python’s built-in open() function, rasterio.open() has two primary arguments: a path (or URL) and an optional mode ('r', 'w', 'r+', or 'w+'). In addition there are a number of keyword arguments, several of which are required when creating a new dataset:

  • driver
  • width, height
  • count
  • dtype
  • crs
  • transform

These same parameters surface in a dataset’s profile property. Exploiting the symmetry between a profile and dataset opening keyword arguments is good Rasterio usage.

with rasterio.open('first.jp2') as src_dataset:

    # Get a copy of the source dataset's profile. Thus our
    # destination dataset will have the same dimensions,
    # number of bands, data type, and georeferencing as the
    # source dataset.
    kwds = src_dataset.profile

    # Change the format driver for the destination dataset to
    # 'GTiff', short for GeoTIFF.
    kwds['driver'] = 'GTiff'

    # Add GeoTIFF-specific keyword arguments.
    kwds['tiled'] = True
    kwds['blockxsize'] = 256
    kwds['blockysize'] = 256
    kwds['photometric'] = 'YCbCr'
    kwds['compress'] = 'JPEG'

    with rasterio.open('second.tif', 'w', **kwds) as dst_dataset:
        # Write data to the destination dataset.

The rasterio.profiles module contains an example of a named profile that may be useful in applications:

class DefaultGTiffProfile(Profile):
    """Tiled, band-interleaved, LZW-compressed, 8-bit GTiff."""

    defaults = {
        'driver': 'GTiff',
        'interleave': 'band',
        'tiled': True,
        'blockxsize': 256,
        'blockysize': 256,
        'compress': 'lzw',
        'nodata': 0,
        'dtype': uint8
    }

It can be used to create new datasets. Note that it doesn’t count bands and that a count keyword argument needs to be passed when creating a profile.

from rasterio.profiles import DefaultGTiffProfile

with rasterio.open(
        'output.tif', 'w', **DefaultGTiffProfile(count=3)) as dst_dataset:
    # Write data to the destination dataset.