Grids
=====

Polar2grid is capable of handling PROJ.4 strings to describe the grids being mapped to.
For more details on each grid see the package provided
`Grids Configuration File <https://github.com/davidh-ssec/polar2grid/blob/master/py/polar2grid/polar2grid/grids/grids.conf>`_.
If you would like to add your own grid see the :doc:`dev_guide/grids` section
of the Developer's Guide. There are additional grids provided in Polar2Grid that
aren't listed here. Some exist for a specific backend (like AWIPS grids), but can be used
for other backends as well.

The following grids are used with the PROJ.4 library (using pyproj bindings)
through the "ll2cr" step of remapping.  See
`PROJ.4 GenParams <http://trac.osgeo.org/proj/wiki/GenParms>`_
for more information on what each parameter means.

.. note::

    If the grid does not have a parameter specified it will be derived from the
    data during remapping.  This allows for grids that fit to the data (dynamic
    grids).

.. _wgs84_fit:

WGS84 Dynamic Fit
^^^^^^^^^^^^^^^^^

:Grid Name: wgs84_fit
:Description: Longitude/Latitude WGS84 Grid
:PROJ.4 String: +proj=latlong +datum=WGS84 +ellps=WGS84 +no_defs
:Grid Width: None
:Grid Height: None
:X Pixel Size: 0.0057 degrees
:Y Pixel Size: 0.0057 degrees
:X Origin: None
:Y Origin: None

WGS84 Dynamic Fit 250m
^^^^^^^^^^^^^^^^^^^^^^

:Grid Name: wgs84_fit_250
:Description: Longitude/Latitude WGS84 Grid at ~250m resolution
:PROJ.4 String: +proj=latlong +datum=WGS84 +ellps=WGS84 +no_defs
:Grid Width: None
:Grid Height: None
:X Pixel Size: 0.00225 degrees
:Y Pixel Size: 0.00225 degrees
:X Origin: None
:Y Origin: None

Lambert Conic Conformal Dynamic Fit
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

:Grid Name: lcc_fit
:Description: 1km East CONUS centered lcc grid
:PROJ.4 String: +proj=lcc +datum=WGS84 +ellps=WGS84 +lat_0=25 +lon_0=-95
:Grid Width: None
:Grid Height: None
:X Pixel Size: 1000 meters
:Y Pixel Size: 1000 meters
:X Origin: None
:Y Origin: None

High Resolution Lambert Conic Conformal Dynamic Fit
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

:Grid Name: lcc_fit_hr
:Description: 400m East CONUS centered lcc grid
:PROJ.4 String: +proj=lcc +datum=WGS84 +ellps=WGS84 +lat_0=25 +lon_0=-95
:Grid Width: None
:Grid Height: None
:X Pixel Size: 400 meters
:Y Pixel Size: 400 meters
:X Origin: None
:Y Origin: None

Polar-Stereographic North Pacific
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

:Grid Name: polar_north_pacific
:Description: 400m Northern Pacific Grid
:PROJ.4 String: +proj=stere +datum=WGS84 +ellps=WGS84 +lat_0=90 +lat_ts=45.0 +lon_0=-170
:Grid Width: None
:Grid Height: None
:X Pixel Size: 400 meters
:Y Pixel Size: 400 meters
:X Origin: None
:Y Origin: None

Polar-Stereographic South Pacific
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

:Grid Name: polar_south_pacific
:Description: 400m Southern Pacific Grid
:PROJ.4 String: +proj=stere +datum=WGS84 +ellps=WGS84 +lat_0=-90 +lat_ts=-45.0 +lon_0=-170
:Grid Width: None
:Grid Height: None
:X Pixel Size: 400 meters
:Y Pixel Size: 400 meters
:X Origin: None
:Y Origin: None

Equirectangular Fit
^^^^^^^^^^^^^^^^^^^

:Grid Name: eqc_fit
:Description: 250m Grid centered over -100 longitude
:PROJ.4 String: +proj=eqc +datum=WGS84 +ellps=WGS84 +lat_ts=0 +lon_0=-100 +units=m +no_defs
:Grid Width: None
:Grid Height: None
:X Pixel Size: 250 meters
:Y Pixel Size: 250 meters
:X Origin: None
:Y Origin: None