#!/bin/env python
# -*- coding: utf-8 -*-
#
#Created on 10.04.17
#
#Created for pymepps
#
#@author: Tobias Sebastian Finn, tobias.sebastian.finn@studium.uni-hamburg.de
#
# Copyright (C) {2017} {Tobias Sebastian Finn}
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# System modules
import logging
# External modules
import numpy as np
# Internal modules
from .lonlat import LonLatGrid
from .unstructured import UnstructuredGrid
logger = logging.getLogger(__name__)
[docs]class CurvilinearGrid(LonLatGrid):
"""
A curvilinear grid could be described as special case of a lonlat grid
where the number of vertices is 4. The raw grid values are calculated based
on the given grid rules. At the moment the lon lat values had to be
precomputed.
"""
def __init__(self, grid_dict):
super().__init__(grid_dict)
self._grid_dict = {
'gridtype': 'curvilinear',
'xlongname': 'longitude',
'xname': 'lon',
'xunits': 'degrees',
'ylongname': 'latitude',
'yname': 'lat',
'yunits': 'degrees',
'nvertex': 4,
}
self._grid_dict.update(grid_dict)
def _calc_lat_lon(self):
y, x = self._construct_dim()
lat = np.array(self._grid_dict['yvals']).reshape(y.size, x.size)
lon = np.array(self._grid_dict['xvals']).reshape(y.size, x.size)
return lat, lon
[docs] def lonlatbox(self, data, ll_box):
"""
The data is sliced as unstructured grid with given lonlat box.
Parameters
----------
data : numpy.ndarray or xarray.DataArray
The data which should be sliced. The shape of the last two
dimensions should be the same as the grid dimensions.
ll_box : tuple(float)
The longitude and latitude box with four entries as degree. The
entries are handled in the following way:
(left/west, top/north, right/east, bottom/south)
Returns
-------
sliced_data : numpy.ndarray or xarray.DataArray
The sliced data with the same type as the input data. If the input
data is a xarray.DataArray the output data will use the same
attributes and non-grid dimensions as the input data.
sliced_grid : UnstructuredGrid
A new UnstructuredGrid with the sliced coordinates as values.
"""
return self._lonlatbox(data, ll_box, unstructured=True)