.. _quick_start:


Quick Start
===========


.. image:: https://dev.azure.com/MPAS-Dev/pyremap%20testing/_apis/build/status/MPAS-Dev.pyremap?branchName=master
   :target: https://dev.azure.com/MPAS-Dev/pyremap%20testing/_build/latest?definitionId=1&branchName=master
   :alt: Build Status


Python remapping tools for climate and earth system models.

Installation
------------

To use the latest version for developers, you will need to set up a conda
environment with the following packages:


* python >= 3.6
* numpy
* scipy
* netcdf4
* xarray >= 0.10.0
* dask
* nco >= 4.8.1
* pyproj

These can be installed via the conda command:

.. code-block::

   conda config --add channels conda-forge
   conda config --set channel_priority strict
   conda create -n pyremap python=3.7 numpy scipy netcdf4 "xarray>=0.10.0" dask \
       "nco>=4.8.1" pyproj
   conda activate pyremap

Then, get the code from:
`https://github.com/MPAS-Dev/pyremap <https://github.com/MPAS-Dev/pyremap>`_

Examples
--------

.. code-block::

   cd examples

The simplest way to make pyremap available is:

.. code-block::

   ln -s ../pyremap

First, make mapping files for a lat-lon grid, and test it out by remapping
temperature from the example file:

.. code-block::

   wget https://web.lcrc.anl.gov/public/e3sm/inputdata/ocn/mpas-o/oQU240/ocean.QU.240km.151209.nc
   ./make_mpas_to_lat_lon_mapping.py

You should now see the mapping file:

.. code-block::

   map_oQU240_to_0.5x0.5degree.nc

as well as the input file (an initial condition for the MPAS-Ocean model) and
an example of temperature from the initial condition remapped to the new grid.

.. code-block::

   ocean.QU.240km.151209.nc
   temp_0.5x0.5degree.nc

Second, let's try the same but to an Antarctic stereographic grid:

.. code-block::

   ./make_mpas_to_Antarctic_stereo_mapping.py

Now, there's a new mapping file and example output file:

.. code-block::

   map_oQU240_to_6000.0x6000.0km_10.0km_Antarctic_stereo.nc
   temp_6000.0x6000.0km_10.0km_Antarctic_stereo.nc

Finally, let's remap the temperature on the Antarctic grid to a lower
resolution Antarctic grid:

.. code-block::

   ./remap_stereographic.py -i temp_6000.0x6000.0km_10.0km_Antarctic_stereo.nc \
       -o temp_6000.0x6000.0km_20.0km_Antarctic_stereo.nc -r 20

This created another mapping file and an output file:

.. code-block::

   map_6000x6000km_10km_Antarctic_stereo_to_6000x6000km_20.0km_Antarctic_stereo.nc
   temp_6000.0x6000.0km_20.0km_Antarctic_stereo.nc