Plotting
============

nctoolkit provides automatic plotting of netCDF data in a similar way to
the command line tool ncview.

If you have a dataset, simply use the ``plot`` method to create an
interactive plot that matches the data type.

We can illustate this using a sea surface temperature dataset available
`here <https://psl.noaa.gov/data/gridded/data.cobe2.html>`__.

Let’s start by calculating mean sea surface temperature for the year
2000 and plotting it:

.. code:: ipython3

    import nctoolkit as nc
    ff =  "sst.mon.mean.nc"
    ds = nc.open_data(ff)
    ds.subset(year = 2000)
    ds.plot()

.. raw:: html
   :file: visualization_plot1.html


We might be interested in the zonal mean. nctoolkit can automatically
plot this easily:

.. code:: ipython3

    ff =  "sst.mon.mean.nc"
    ds = nc.open_data(ff)
    ds.subset(year = 2000)
    ds.tmean()
    ds.zonal_mean()
    ds.plot()

.. raw:: html
   :file: visualization_plot2.html

nctoolkit can also easily handle heat maps. So, we can easily plot the change in zonal mean over time:



.. code:: ipython3

        ff =  "sst.mon.mean.nc"
        ds = nc.open_data(ff)
        ds.zonal_mean()
        ds.annual_anomaly(baseline = [1850, 1869], window = 20)gg
        ds.plot()

.. raw:: html
   :file: visualization_plot3.html

In a similar vein, it can automatically handle time series. Below we plot a time series of global mean sea surface temperature since 1850:


.. code:: ipython3

        ff =  "sst.mon.mean.nc"
        ds = nc.open_data(ff)
        ds.spatial_mean()
        ds.plot()

.. raw:: html
   :file: visualization_plot4.html

Publication quality plots
---------------------

The ability to produce plots that are at or close to publication quality was introduced in version 0.9.2 in nctoolkit.
This is carried out using the ``pub_plot`` method, and is designed to quickly produce a plot that is suitable for a publication or presentation.

.. code:: ipython3

        ff =  "sst.mon.mean.nc"
        ds = nc.open_data(ff)
        ds.tmean()
        ds.pub_plot()

.. image:: pub_plot1.png
   :width: 100%
   :align: center
   :alt: pub_plot1

Currently, ``pub_plot`` is restricted to work with regular lon/lat grids. A limited number of modifications can be made, such as changes to the colour scale. Over-time this will become a fully featured method.


Plotting internals
---------------------
Plotting is carried out using the ncplot package. ncplot will look at the dataset and identify a suitable plotting method. This is carried out internally using hvplot. If you come across any errors, 
please raise an issue `here <https://github.com/pmlmodelling/ncplot>`__.

This is a package that aims to deliver plotting for rapid exploratory analysis, and therefore it does not offer a large number of customizations. However, because it is built on hvplot, you can use most of the customization options available in hvplot, which are detailed `here <https://hvplot.holoviz.org/user_guide/Customization.html>`__. Arguments such as `title`, `logz` and `clim` can be passed to `plot` and will be automatically passed to the hvplot method used
.