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#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (c) 2014-2022 Pytroll developers
#
#
# 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/>.
"""Read the Terra/Aqua MODIS relative spectral response functions."""
import logging
import os
import numpy as np
from pyspectral.config import get_config
from pyspectral.utils import get_central_wave, sort_data
LOG = logging.getLogger(__name__)
MODIS_BAND_NAMES = [str(i) for i in range(1, 37)]
SHORTWAVE_BANDS = [str(i) for i in list(range(1, 20)) + [26]]
class ModisRSR(object):
"""Container for the Terra/Aqua RSR data."""
def __init__(self, bandname, platform_name, sort=True):
"""Initialize the Modis RSR class."""
self.platform_name = platform_name
self.bandname = bandname
self.filenames = {}
self.requested_band_filename = None
self.is_sw = False
if bandname in SHORTWAVE_BANDS:
self.is_sw = True
self.scales = {}
for bname in MODIS_BAND_NAMES:
self.filenames[bname] = None
self.rsr = None
self._sort = sort
options = get_config()
self.path = options[platform_name + '-modis'].get('path')
self.output_dir = options.get('rsr_dir', './')
self._get_bandfilenames()
LOG.debug("Filenames: %s", str(self.filenames))
if os.path.exists(self.filenames[bandname]):
self.requested_band_filename = self.filenames[bandname]
self._load()
else:
raise IOError("Couldn't find an existing file for this band: " +
str(self.bandname))
def _get_bandfilenames(self):
"""Get the MODIS rsr filenames."""
path = self.path
for band in MODIS_BAND_NAMES:
bnum = int(band)
LOG.debug("Band = %s", str(band))
if self.platform_name == 'EOS-Terra':
filename = os.path.join(path,
"rsr.{0:d}.inb.final".format(bnum))
else:
if bnum in [5, 6, 7] + list(range(20, 37)):
filename = os.path.join(
path, "{0:>02d}.tv.1pct.det".format(bnum))
else:
filename = os.path.join(
path, "{0:>02d}.amb.1pct.det".format(bnum))
self.filenames[band] = filename
def _load(self):
"""Load the MODIS RSR data for the band requested."""
if self.is_sw or self.platform_name == 'EOS-Aqua':
scale = 0.001
else:
scale = 1.0
detector = read_modis_response(self.requested_band_filename, scale)
self.rsr = detector
if self._sort:
self.sort()
def sort(self):
"""Sort the data so that x is monotonically increasing and contains no duplicates."""
if 'wavelength' in self.rsr:
# Only one detector apparently:
self.rsr['wavelength'], self.rsr['response'] = \
sort_data(self.rsr['wavelength'], self.rsr['response'])
else:
for detector_name in self.rsr:
(self.rsr[detector_name]['wavelength'],
self.rsr[detector_name]['response']) = \
sort_data(self.rsr[detector_name]['wavelength'],
self.rsr[detector_name]['response'])
def read_modis_response(filename, scale=1.0):
"""Read the Terra/Aqua MODIS relative spectral responses.
Be aware that MODIS has several detectors (more than one) compared to
e.g. AVHRR which has always only one.
"""
with open(filename, "r") as fid:
lines = fid.readlines()
nodata = -99.0
# The IR channels seem to be in microns, whereas the short wave channels are
# in nanometers! For VIS/NIR scale should be 0.001
detectors = {}
for line in lines:
if line.find("#") == 0:
continue
dummy, det_num, s_1, s_2 = line.split()
detector_name = 'det-{0:d}'.format(int(det_num))
if detector_name not in detectors:
detectors[detector_name] = {'wavelength': [], 'response': []}
detectors[detector_name]['wavelength'].append(float(s_1) * scale)
detectors[detector_name]['response'].append(float(s_2))
for key in detectors:
mask = np.array(detectors[key]['response']) == nodata
detectors[key]['response'] = np.ma.masked_array(
detectors[key]['response'], mask=mask).compressed()
detectors[key]['wavelength'] = np.ma.masked_array(
detectors[key]['wavelength'], mask=mask).compressed()
return detectors
def convert2hdf5(platform_name):
"""Retrieve original RSR data and convert to internal hdf5 format."""
import h5py
modis = ModisRSR('20', platform_name)
mfile = os.path.join(modis.output_dir,
"rsr_modis_{platform}.h5".format(platform=platform_name))
with h5py.File(mfile, "w") as h5f:
h5f.attrs['description'] = 'Relative Spectral Responses for MODIS'
h5f.attrs['platform_name'] = platform_name
h5f.attrs['band_names'] = MODIS_BAND_NAMES
for chname in MODIS_BAND_NAMES:
modis = ModisRSR(chname, platform_name)
grp = h5f.create_group(chname)
grp.attrs['number_of_detectors'] = len(modis.rsr.keys())
# Loop over each detector to check if the sampling wavelengths are
# identical:
det_names = [detector_name for detector_name in modis.rsr.keys()]
wvl = modis.rsr[det_names[0]]['wavelength']
wvl_is_constant = True
for det in det_names[1:]:
if wvl.shape != modis.rsr[det]['wavelength'].shape:
wvl_is_constant = False
break
elif not np.allclose(wvl, modis.rsr[det]['wavelength']):
wvl_is_constant = False
break
if wvl_is_constant:
arr = modis.rsr[det_names[0]]['wavelength']
dset = grp.create_dataset('wavelength', arr.shape, dtype='f')
dset.attrs['unit'] = 'm'
dset.attrs['scale'] = 1e-06
dset[...] = arr
# Loop over each detector:
for det in modis.rsr:
det_grp = grp.create_group(det)
wvl = modis.rsr[det]['wavelength'][
~np.isnan(modis.rsr[det]['wavelength'])]
rsp = modis.rsr[det]['response'][
~np.isnan(modis.rsr[det]['wavelength'])]
det_grp.attrs[
'central_wavelength'] = get_central_wave(wvl, rsp)
if not wvl_is_constant:
arr = modis.rsr[det]['wavelength']
dset = det_grp.create_dataset(
'wavelength', arr.shape, dtype='f')
dset.attrs['unit'] = 'm'
dset.attrs['scale'] = 1e-06
dset[...] = arr
arr = modis.rsr[det]['response']
dset = det_grp.create_dataset('response', arr.shape, dtype='f')
dset[...] = arr
if __name__ == "__main__":
for sat in ['EOS-Terra', 'EOS-Aqua']:
convert2hdf5(sat)
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