/
hdfeos_base.py
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/
hdfeos_base.py
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#!/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/>.
"""Base HDF-EOS reader."""
import re
import logging
from datetime import datetime
import xarray as xr
import numpy as np
from pyhdf.error import HDF4Error
from pyhdf.SD import SD
from satpy import CHUNK_SIZE
from satpy.readers.file_handlers import BaseFileHandler
logger = logging.getLogger(__name__)
def interpolate(clons, clats, csatz, src_resolution, dst_resolution):
"""Interpolate two parallel datasets jointly."""
from geotiepoints.modisinterpolator import modis_1km_to_250m, modis_1km_to_500m, modis_5km_to_1km
interpolation_functions = {
(5000, 1000): modis_5km_to_1km,
(1000, 500): modis_1km_to_500m,
(1000, 250): modis_1km_to_250m
}
try:
interpolation_function = interpolation_functions[(src_resolution, dst_resolution)]
except KeyError:
error_message = "Interpolation from {}m to {}m not implemented".format(
src_resolution, dst_resolution)
raise NotImplementedError(error_message)
logger.debug("Interpolating from {} to {}".format(src_resolution, dst_resolution))
return interpolation_function(clons, clats, csatz)
class HDFEOSBaseFileReader(BaseFileHandler):
"""Base file handler for HDF EOS data for both L1b and L2 products."""
def __init__(self, filename, filename_info, filetype_info):
"""Initialize the base reader."""
BaseFileHandler.__init__(self, filename, filename_info, filetype_info)
try:
self.sd = SD(self.filename)
except HDF4Error as err:
error_message = "Could not load data from file {}: {}".format(self.filename, err)
raise ValueError(error_message)
# Read metadata
self.metadata = self.read_mda(self.sd.attributes()['CoreMetadata.0'])
self.metadata.update(self.read_mda(
self.sd.attributes()['StructMetadata.0'])
)
self.metadata.update(self.read_mda(
self.sd.attributes()['ArchiveMetadata.0'])
)
@staticmethod
def read_mda(attribute):
"""Read the EOS metadata."""
lines = attribute.split('\n')
mda = {}
current_dict = mda
path = []
prev_line = None
for line in lines:
if not line:
continue
if line == 'END':
break
if prev_line:
line = prev_line + line
key, val = line.split('=')
key = key.strip()
val = val.strip()
try:
val = eval(val)
except NameError:
pass
except SyntaxError:
prev_line = line
continue
prev_line = None
if key in ['GROUP', 'OBJECT']:
new_dict = {}
path.append(val)
current_dict[val] = new_dict
current_dict = new_dict
elif key in ['END_GROUP', 'END_OBJECT']:
if val != path[-1]:
raise SyntaxError
path = path[:-1]
current_dict = mda
for item in path:
current_dict = current_dict[item]
elif key in ['CLASS', 'NUM_VAL']:
pass
else:
current_dict[key] = val
return mda
@property
def start_time(self):
"""Get the start time of the dataset."""
date = (self.metadata['INVENTORYMETADATA']['RANGEDATETIME']['RANGEBEGINNINGDATE']['VALUE'] + ' ' +
self.metadata['INVENTORYMETADATA']['RANGEDATETIME']['RANGEBEGINNINGTIME']['VALUE'])
return datetime.strptime(date, '%Y-%m-%d %H:%M:%S.%f')
@property
def end_time(self):
"""Get the end time of the dataset."""
date = (self.metadata['INVENTORYMETADATA']['RANGEDATETIME']['RANGEENDINGDATE']['VALUE'] + ' ' +
self.metadata['INVENTORYMETADATA']['RANGEDATETIME']['RANGEENDINGTIME']['VALUE'])
return datetime.strptime(date, '%Y-%m-%d %H:%M:%S.%f')
def _read_dataset_in_file(self, dataset_name):
if dataset_name not in self.sd.datasets():
error_message = "Dataset name {} not included in available datasets {}".format(
dataset_name, self.sd.datasets()
)
raise KeyError(error_message)
dataset = self.sd.select(dataset_name)
return dataset
def load_dataset(self, dataset_name):
"""Load the dataset from HDF EOS file."""
from satpy.readers.hdf4_utils import from_sds
dataset = self._read_dataset_in_file(dataset_name)
fill_value = dataset._FillValue
dask_arr = from_sds(dataset, chunks=CHUNK_SIZE)
dims = ('y', 'x') if dask_arr.ndim == 2 else None
data = xr.DataArray(dask_arr, dims=dims,
attrs=dataset.attributes())
# preserve integer data types if possible
if np.issubdtype(data.dtype, np.integer):
new_fill = fill_value
else:
new_fill = np.nan
data.attrs.pop('_FillValue', None)
good_mask = data != fill_value
scale_factor = data.attrs.get('scale_factor')
if scale_factor is not None:
data = data * scale_factor
data = data.where(good_mask, new_fill)
return data
class HDFEOSGeoReader(HDFEOSBaseFileReader):
"""Handler for the geographical datasets."""
# list of geographical datasets handled by the georeader
# mapping to the default variable name if not specified in YAML
DATASET_NAMES = {
'longitude': 'Longitude',
'latitude': 'Latitude',
'satellite_azimuth_angle': ('SensorAzimuth', 'Sensor_Azimuth'),
'satellite_zenith_angle': ('SensorZenith', 'Sensor_Zenith'),
'solar_azimuth_angle': ('SolarAzimuth', 'SolarAzimuth'),
'solar_zenith_angle': ('SolarZenith', 'Solar_Zenith'),
}
def __init__(self, filename, filename_info, filetype_info):
"""Initialize the geographical reader."""
HDFEOSBaseFileReader.__init__(self, filename, filename_info, filetype_info)
self.cache = {}
@staticmethod
def read_geo_resolution(metadata):
"""Parse metadata to find the geolocation resolution.
It is implemented as a staticmethod to match read_mda pattern.
"""
# level 1 files
try:
ds = metadata['INVENTORYMETADATA']['COLLECTIONDESCRIPTIONCLASS']['SHORTNAME']['VALUE']
if ds.endswith('D03'):
return 1000
else:
# 1km files have 5km geolocation usually
return 5000
except KeyError:
pass
# data files probably have this level 2 files
# this does not work for L1B 1KM data files because they are listed
# as 1KM data but the geo data inside is at 5km
try:
latitude_dim = metadata['SwathStructure']['SWATH_1']['DimensionMap']['DimensionMap_2']['GeoDimension']
resolution_regex = re.compile(r'(?P<resolution>\d+)(km|KM)')
resolution_match = resolution_regex.search(latitude_dim)
return int(resolution_match.group('resolution')) * 1000
except (AttributeError, KeyError):
pass
raise RuntimeError("Could not determine resolution from file metadata")
@property
def geo_resolution(self):
"""Resolution of the geographical data retrieved in the metadata."""
return self.read_geo_resolution(self.metadata)
def _load_ds_by_name(self, ds_name):
"""Attempt loading using multiple common names."""
var_names = self.DATASET_NAMES[ds_name]
if isinstance(var_names, (list, tuple)):
try:
return self.load_dataset(var_names[0])
except KeyError:
return self.load_dataset(var_names[1])
return self.load_dataset(var_names)
def get_interpolated_dataset(self, name1, name2, resolution, sensor_zenith, offset=0):
"""Load and interpolate datasets."""
try:
result1 = self.cache[(name1, resolution)]
result2 = self.cache[(name2, resolution)]
except KeyError:
result1 = self._load_ds_by_name(name1)
result2 = self._load_ds_by_name(name2) - offset
result1, result2 = interpolate(
result1, result2, sensor_zenith,
self.geo_resolution, resolution
)
self.cache[(name1, resolution)] = result1
self.cache[(name2, resolution)] = result2 + offset
def get_dataset(self, dataset_keys, dataset_info):
"""Get the geolocation dataset."""
# Name of the dataset as it appears in the HDF EOS file
in_file_dataset_name = dataset_info.get('file_key')
# Name of the dataset in the YAML file
dataset_name = dataset_keys.name
# Resolution asked
resolution = dataset_keys.resolution
if in_file_dataset_name is not None:
# if the YAML was configured with a specific name use that
data = self.load_dataset(in_file_dataset_name)
else:
# otherwise use the default name for this variable
data = self._load_ds_by_name(dataset_name)
if resolution != self.geo_resolution:
if in_file_dataset_name is not None:
# they specified a custom variable name but
# we don't know how to interpolate this yet
raise NotImplementedError(
"Interpolation for variable '{}' is not "
"configured".format(dataset_name))
# The data must be interpolated
sensor_zenith = self._load_ds_by_name('satellite_zenith_angle')
logger.debug("Loading %s", dataset_name)
if dataset_name in ['longitude', 'latitude']:
self.get_interpolated_dataset('longitude', 'latitude',
resolution, sensor_zenith)
elif dataset_name in ['satellite_azimuth_angle', 'satellite_zenith_angle']:
# Sensor dataset names differs between L1b and L2 products
self.get_interpolated_dataset('satellite_azimuth_angle', 'satellite_zenith_angle',
resolution, sensor_zenith, offset=90)
elif dataset_name in ['solar_azimuth_angle', 'solar_zenith_angle']:
# Sensor dataset names differs between L1b and L2 products
self.get_interpolated_dataset('solar_azimuth_angle', 'solar_zenith_angle',
resolution, sensor_zenith, offset=90)
data = self.cache[dataset_name, resolution]
for key in ('standard_name', 'units'):
if key in dataset_info:
data.attrs[key] = dataset_info[key]
return data