1Writing Datasets 2================= 3 4.. todo:: 5 6 * appending to existing data 7 * context manager 8 * write 3d vs write 2d 9 * document issues with writing compressed files (per #77) 10 * discuss and refer to topics 11 * creation options 12 * transforms 13 * dtypes 14 * block windows 15 16Opening a file in writing mode is a little more complicated than opening 17a text file in Python. The dimensions of the raster dataset, the 18data types, and the specific format must be specified. 19 20Here's an example of basic rasterio functionality. 21An array is written to a new single band TIFF. 22 23.. code-block:: python 24 25 # Register GDAL format drivers and configuration options with a 26 # context manager. 27 with rasterio.Env(): 28 29 # Write an array as a raster band to a new 8-bit file. For 30 # the new file's profile, we start with the profile of the source 31 profile = src.profile 32 33 # And then change the band count to 1, set the 34 # dtype to uint8, and specify LZW compression. 35 profile.update( 36 dtype=rasterio.uint8, 37 count=1, 38 compress='lzw') 39 40 with rasterio.open('example.tif', 'w', **profile) as dst: 41 dst.write(array.astype(rasterio.uint8), 1) 42 43 # At the end of the ``with rasterio.Env()`` block, context 44 # manager exits and all drivers are de-registered. 45 46Writing data mostly works as with a Python file. There are a few format- 47specific differences. 48 49Supported Drivers 50----------------- 51``GTiff`` is the only driver that supports writing directly to disk. 52GeoTiffs use the ``RasterUpdater`` and leverage the full capabilities 53of the ``GDALCreate`` function. We highly recommend using GeoTiff 54driver for writing as it is the best-tested and best-supported format. 55 56Some other formats that are writable by GDAL can also be written by 57Rasterio. These use an ``IndirectRasterUpdater`` which does not create 58directly but uses a temporary in-memory dataset and ``GDALCreateCopy`` 59to produce the final output. 60 61Some formats are known to produce invalid results using the 62``IndirectRasterUpdater``. These formats will raise a ``RasterioIOError`` 63if you attempt to write to the. Currently this applies to the ``netCDF`` 64driver but please let us know if you experience problems writing other formats. 65