.. _getting_started:

Getting Started
================

Welcome! This page aims to help you gain a foundational understanding of rioxarray.

rio accessor
-------------

rioxarray `extends xarray <http://xarray.pydata.org/en/stable/internals.html#extending-xarray>`__
with the `rio` accessor. The `rio` accessor is activated by importing rioxarray like so:

.. code-block:: python

    import rioxarray


You can learn how to `clip`, `merge`, and `reproject` rasters in the :ref:`usage_examples`
section of the documentation. Need to export to a raster (GeoTiff)? There is an example for
that as well.


Reading Files
-------------

xarray
~~~~~~~

Since `rioxarray` is an extension of `xarray`, you can load in files using the standard
`xarray` open methods. If you use one of xarray's open methods such as ``xarray.open_dataset``
to load netCDF files with the default engine, it is recommended to use `decode_coords="all"`.
This will load the grid mapping variable into coordinates for compatibility with rioxarray.

.. code-block:: python

    import xarray

    xds = xarray.open_dataset("file.nc", decode_coords="all")


rioxarray
~~~~~~~~~~

rioxarray 0.4+ enables passing `engine="rasterio"` to ``xarray.open_dataset``
and ``xarray.open_mfdataset`` for xarray 0.18+. This uses
:func:`rioxarray.open_rasterio` as the backend and always returns an ``xarray.Dataset``.

.. code-block:: python

    import xarray

    xds = xarray.open_dataset("my.tif", engine="rasterio")

You can also use :func:`rioxarray.open_rasterio`. This objects returned depend on
your input file type.

.. code-block:: python

    import rioxarray

    xds = rioxarray.open_rasterio("my.tif")


Why use :func:`rioxarray.open_rasterio` instead of `xarray.open_rasterio`?

1. It supports multidimensional datasets such as netCDF.
2. It stores the CRS as a WKT, which is the recommended format (`PROJ FAQ <https://proj.org/faq.html#what-is-the-best-format-for-describing-coordinate-reference-systems>`__).
3. It loads in the CRS, transform, and nodata metadata in standard CF & GDAL locations.
4. It supports masking and scaling data with the `masked` and `mask_and_scale` kwargs.
5. It adds the coordinate axis CF metadata.
6. It loads raster metadata into the attributes.
7. `xarray.open_rasterio` is deprecated (since v0.20.0)


Introductory Information
--------------------------

.. toctree::
   :maxdepth: 1

   crs_management.ipynb
   nodata_management.ipynb
   manage_information_loss.ipynb
