Grain Axis Brackets
============================================

In some cases, one might wish to group similar grain sizes, for example, sand or ash grains. This is carried out by default for all of the available grain size presets discussed in the previous section, but can also be removed, or adjusted manually by passing a dictionary to the ``grain_brackets`` argument of ``sp.load()``. 

This parameter has default values for all of the available grain size presets, an example of which for the default clastic grainsize axis is illustrated below.


    .. code-block:: python

        grain_brackets = {'sand': [3, 5], 'gravel': [6, 7.5]}
        log = sp.load('tutorial.csv', grain_brackets=grain_brackets)

    .. image:: ../../_static/reference/axes_sedimentary.png
        :alt: Sedimentary grain size brackets
        :height: 100px

The grain brackets functionality can be removed by passing an empty dictionary to the ``grain_brackets`` argument:

.. code-block:: python

    log = sp.load('file.csv', grain_brackets={})

Alternatively, you can provide a custom dictionary to match either a preset or your own grain sizes provided in ``x_ticks_dict``.

For example, to change the brackets of the default 'clastic' preset:

.. code-block:: python

    grain_brackets = brackets = {
        'powders': (1, 2),
        'sands': (3, 5),
        'rocks': (6, 7.5)
    }
    log = sp.load('file.csv', grain_brackets=grain_brackets)

.. image:: ../../_static/reference/axes_custom_brackets.png
   :alt: Custom grain size brackets
   :width: 70%

Alternatively, we can specify a custom dictionary of grain sizes and brackets:

.. code-block:: python

    x_ticks = { 'mud': .5, 'silt': 1.5, 'v.f.': 3, 'f': 3.5, 'm': 4, 'c': 4.5, 'v.c.': 5, 'peb': 6, 'cob': 6.75, 'bld': 7.5 }
    brackets = { 
        'powders': (.5, 1.5), 
        'sands': (3, 5), 
        'rocks': (6, 7.5) 
    }
    log = sp.load('file.csv', x_ticks_dict=x_ticks, grain_brackets=brackets)

.. image:: ../../_static/reference/axes_custom_ticks_brackets.png
   :alt: Custom grain size brackets
   :width: 70%