#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2019 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/>.
"""SAFE SAR L2 OCN format reader.
The OCN data contains various parameters, but mainly the wind speed and direction
calculated from SAR data and input model data from ECMWF
Implemented in this reader is the OWI, Ocean Wind field.
See more at ESA webpage https://sentinel.esa.int/web/sentinel/ocean-wind-field-component
"""
import logging
import numpy as np
import xarray as xr
from satpy.readers.file_handlers import BaseFileHandler
from satpy.utils import get_legacy_chunk_size
logger = logging.getLogger(__name__)
CHUNK_SIZE = get_legacy_chunk_size()
[docs]
class SAFENC(BaseFileHandler):
"""Measurement file reader."""
def __init__(self, filename, filename_info, filetype_info):
"""Init the file reader."""
super(SAFENC, self).__init__(filename, filename_info,
filetype_info)
self._start_time = filename_info["start_time"]
self._end_time = filename_info["end_time"]
# For some SAFE packages, fstart_time differs, but start_time is the same
# To avoid over writing exiting file with same start_time, a solution is to
# use fstart_time
self._fstart_time = filename_info["fstart_time"]
self._fend_time = filename_info["fend_time"]
self._polarization = filename_info["polarization"]
self.lats = None
self.lons = None
self._shape = None
self.area = None
self.nc = xr.open_dataset(filename,
decode_cf=True,
mask_and_scale=False,
chunks={"owiAzSize": CHUNK_SIZE,
"owiRaSize": CHUNK_SIZE})
self.nc = self.nc.rename({"owiAzSize": "y"})
self.nc = self.nc.rename({"owiRaSize": "x"})
self.filename = filename
[docs]
def get_dataset(self, key, info):
"""Load a dataset."""
if key["name"] in ["owiLat", "owiLon"]:
if self.lons is None or self.lats is None:
self.lons = self.nc["owiLon"]
self.lats = self.nc["owiLat"]
if key["name"] == "owiLat":
res = self.lats
else:
res = self.lons
res.attrs = info
else:
res = self._get_data_channels(key, info)
if "missionName" in self.nc.attrs:
res.attrs.update({"platform_name": self.nc.attrs["missionName"]})
res.attrs.update({"fstart_time": self._fstart_time})
res.attrs.update({"fend_time": self._fend_time})
if not self._shape:
self._shape = res.shape
return res
[docs]
def _get_data_channels(self, key, info):
res = self.nc[key["name"]]
if key["name"] in ["owiHs", "owiWl", "owiDirmet"]:
res = xr.DataArray(res, dims=["y", "x", "oswPartitions"])
elif key["name"] in ["owiNrcs", "owiNesz", "owiNrcsNeszCorr"]:
res = xr.DataArray(res, dims=["y", "x", "oswPolarisation"])
elif key["name"] in ["owiPolarisationName"]:
res = xr.DataArray(res, dims=["owiPolarisation"])
elif key["name"] in ["owiCalConstObsi", "owiCalConstInci"]:
res = xr.DataArray(res, dims=["owiIncSize"])
elif key["name"].startswith("owi"):
res = xr.DataArray(res, dims=["y", "x"])
else:
res = xr.DataArray(res, dims=["y", "x"])
res.attrs.update(info)
if "_FillValue" in res.attrs:
res = res.where(res != res.attrs["_FillValue"])
res.attrs["_FillValue"] = np.nan
return res
@property
def start_time(self):
"""Product start_time, parsed from the measurement file name."""
return self._start_time
@property
def end_time(self):
"""Product end_time, parsed from the measurement file name."""
return self._end_time
@property
def fstart_time(self):
"""Product fstart_time meaning the start time parsed from the SAFE directory."""
return self._fstart_time
@property
def fend_time(self):
"""Product fend_time meaning the end time parsed from the SAFE directory."""
return self._fend_time