#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2020 Satpy developers
#
# This file is part of satpy.
#
# satpy 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.
#
# satpy 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
# satpy. If not, see <http://www.gnu.org/licenses/>.
"""SMOS L2 wind Reader.
Data can be found here after register:
https://www.smosstorm.org/Data2/SMOS-NRT-wind-Products-access
Format documentation at the same site after register:
SMOS_WIND_DS_PDD_20191107_signed.pdf
"""
import logging
from datetime import datetime
import numpy as np
from pyresample.geometry import AreaDefinition
from satpy.readers.netcdf_utils import NetCDF4FileHandler, netCDF4
logger = logging.getLogger(__name__)
[docs]class SMOSL2WINDFileHandler(NetCDF4FileHandler):
"""File handler for SMOS L2 wind netCDF files."""
@property
def start_time(self):
"""Get start time."""
return datetime.strptime(self['/attr/time_coverage_start'], "%Y-%m-%dT%H:%M:%S Z")
@property
def end_time(self):
"""Get end time."""
return datetime.strptime(self['/attr/time_coverage_end'], "%Y-%m-%dT%H:%M:%S Z")
@property
def platform_shortname(self):
"""Get platform shortname."""
return self.filename_info['platform_shortname']
@property
def platform_name(self):
"""Get platform."""
return self['/attr/platform']
[docs] def available_datasets(self, configured_datasets=None):
"""Automatically determine datasets provided by this file."""
handled_variables = set()
# Iterate over dataset contents
for var_name, val in self.file_content.items():
# Only evaluate variables
if not isinstance(val, netCDF4.Variable):
continue
if (var_name in handled_variables):
logger.debug("Already handled, skipping: %s", var_name)
continue
handled_variables.add(var_name)
new_info = {
'name': var_name,
'file_type': self.filetype_info['file_type'],
}
yield True, new_info
def _mask_dataset(self, data):
"""Mask out fill values."""
try:
fill = data.attrs['_FillValue']
data.attrs['_FillValue'] = np.nan
return data.where(data != fill)
except KeyError:
return data
def _adjust_lon_coord(self, data):
"""Adjust lon coordinate to -180 .. 180 ( not 0 .. 360)."""
data = data.assign_coords(lon=(((data.lon + 180) % 360) - 180))
return data.where(data < 180., data - 360.)
def _rename_coords(self, data):
"""Rename coords."""
rename_dict = {}
if 'lon' in data.dims:
data = self._adjust_lon_coord(data)
rename_dict['lon'] = 'x'
if 'lat' in data.dims:
rename_dict['lat'] = 'y'
# Rename the coordinates to x and y
return data.rename(rename_dict)
def _remove_time_coordinate(self, data):
"""Remove time coordinate."""
# Remove dimension where size is 1, eg. time
data = data.squeeze()
# Remove if exists time as coordinate
if 'time' in data.coords:
data = data.drop_vars('time')
return data
def _roll_dataset_lon_coord(self, data):
"""Roll dataset along the lon coordinate."""
if 'lon' in data.dims:
data = data.roll(lon=720, roll_coords=True)
return data
[docs] def get_dataset(self, ds_id, ds_info):
"""Get dataset."""
data = self[ds_id['name']]
data.attrs = self.get_metadata(data, ds_info)
data = self._remove_time_coordinate(data)
data = self._roll_dataset_lon_coord(data)
data = self._rename_coords(data)
data = self._mask_dataset(data)
if len(data.dims) >= 2 and all([dim in data.dims for dim in ['x', 'y']]):
# Remove the first and last row as these values extends beyond +-90 latitude
# if the dataset contains the y dimmension.
# As this is data over open sea these has no values.
data = data.where((data.y > -90.0) & (data.y < 90.0), drop=True)
elif len(data.dims) == 1 and 'y' in data.dims:
data = data.where((data.y > 0) & (data.y < len(data.y) - 1), drop=True)
return data
def _create_area_extent(self, width, height):
"""Create area extent."""
# Creating a meshgrid, not needed actually, but makes it easy to find extremes
_lon = self._adjust_lon_coord(self['lon'])
_lon = self._roll_dataset_lon_coord(_lon)
latlon = np.meshgrid(_lon, self['lat'][1:self['lat/shape'][0] - 1])
lower_left_x = latlon[0][height - 1][0] - 0.125
lower_left_y = latlon[1][height - 1][0] + 0.125
upper_right_y = latlon[1][1][width - 1] - 0.125
upper_right_x = latlon[0][1][width - 1] + 0.125
return (lower_left_x, lower_left_y, upper_right_x, upper_right_y)
[docs] def get_area_def(self, dsid):
"""Define AreaDefintion."""
width = self['lon/shape'][0]
height = self['lat/shape'][0] - 2
area_extent = self._create_area_extent(width, height)
description = "SMOS L2 Wind Equirectangular Projection"
area_id = 'smos_eqc'
proj_id = 'equirectangular'
proj_dict = {'init': self['/attr/geospatial_bounds_vertical_crs']}
area_def = AreaDefinition(area_id, description, proj_id, proj_dict, width, height, area_extent, )
return area_def