pysiral.grid
============

.. py:module:: pysiral.grid

.. autoapi-nested-parse::

   Created on Sun Jun 11 19:24:04 2017

   @author: Stefan



Classes
-------

.. autoapisummary::

   pysiral.grid.GridDefinition
   pysiral.grid.GridTrajectoryExtract


Module Contents
---------------

.. py:class:: GridDefinition(preset=None)

   Bases: :py:obj:`pysiral.core.legacy_classes.DefaultLoggingClass`


   A container class for geospatial grids.  The main components are
   a) the projection (based on pyproj) and b) the extent and grid size.
   The class is currently designed for stereographic/equal area projection
   types. 


   .. py:attribute:: _preset
      :value: None



   .. py:attribute:: _metadata


   .. py:attribute:: _griddef_filename
      :value: None



   .. py:attribute:: _proj
      :value: None



   .. py:attribute:: _proj_dict


   .. py:attribute:: _extent_dict


   .. py:method:: set_from_griddef_file(filename)

      Initialize the object with a grid definition (.yaml) file.
      Examples can be found in pysiral/settings/griddef 



   .. py:method:: set_projection(**kwargs)


   .. py:method:: proj(longitude, latitude, **kwargs)


   .. py:method:: grid_indices(longitude, latitude)

      Computes the grid indices the given lon/lat pairs would be sorted
      into (no clipping) 



   .. py:method:: get_grid_coordinates(mode='center')

      Returns longitude/latitude points for each grid cell
      Note: mode keyword only for future use. center coordinates are
      returned by default 



   .. py:method:: set_extent(**kwargs)


   .. py:method:: _set_proj()


   .. py:property:: hemisphere


   .. py:property:: grid_id


   .. py:property:: grid_tag


   .. py:property:: grid_name


   .. py:property:: resolution_tag


   .. py:property:: proj_dict


   .. py:property:: extent


   .. py:property:: area_extent


   .. py:property:: resolution


   .. py:property:: pyresample_area_def

      Returns a pyresample.geometry.AreaDefinition instance 



   .. py:property:: xc


   .. py:property:: yc


   .. py:property:: xc_km


   .. py:property:: yc_km


   .. py:property:: netcdf_vardef


.. py:class:: GridTrajectoryExtract(trajectory_longitude: numpy.typing.NDArray, trajectory_latitude: numpy.typing.NDArray, griddef: Union[dict, pysiral.core.legacy_classes.AttrDict])

   Bases: :py:obj:`object`


   Implements fast extraction of gridded data along a track using Image Interpolation.
   This class computes the track coordinates in image coordinates upon initialization
   and then allows to extract the multiple variables.

   Requirements are the longitude, latitude values of the trajectory and the projection
   and extent of the grid.

   Usage
   -----

   .. code-block:: python

       grid2track = GridTrajectoryExtract(track_longitude, track_latitude, grid_def)
       track_var_01 = grid2track.get_from_grid_variable(grid_var_01, outside_value=outside_value_01)
       track_var_02 = grid2track.get_from_grid_variable(grid_var_02, outside_value=outside_value_02)
       ...



   .. py:attribute:: trajectory_longitude


   .. py:attribute:: trajectory_latitude


   .. py:attribute:: griddef


   .. py:attribute:: p


   .. py:method:: _get_track_image_coordinates() -> Tuple[numpy.typing.NDArray, numpy.typing.NDArray]

      Computes and returns the image coordinates, by converting the
      trajectory lon/lat values to projection coordinates and
      scaling them tho the grid extent

      :raises: None

      :return: image x coordindate, image y coordinate



   .. py:method:: get_from_grid_variable(grid_var: numpy.typing.NDArray, order: int = 0, flipud: bool = False, outside_value: Any = np.nan) -> numpy.typing.NDArray

      Returns the grid variable along the trajectory using interpolation
      with the specified order. If required the grid var can be flipped
      upside down before extraction (flipud = True).

      :param grid_var: The gridded variable
      :param order: Order of the image interpolation (see scipy.ndimage.map_coordinates)
      :param flipud: Flag if the grid variable should be flipped before extraction.
      :param outside_value: Value to be used for part of the trajectory outside the grid

      :raises: None

      :return: The grid variable extracted and interpolation for the trajectory location