def create_envi_spectral_library(self, spectrumIDs, bandInfo):
'''Creates an ENVI-formatted spectral library for a list of spectra.
Arguments:
`spectrumIDs` (list of ints):
List of **SampleID** values for of spectra in the "Samples"
table of the USGS database.
`bandInfo` (:class:`~spectral.BandInfo`):
The spectral bands to which the original USGS library spectra
will be resampled.
Returns:
A :class:`~spectral.io.envi.SpectralLibrary` object.
The IDs passed to the method should correspond to the SampleID field
of the USGS database "Samples" table. All specified spectra will be
resampled to the same discretization specified by the bandInfo
parameter. See :class:`spectral.BandResampler` for details on the
resampling method used.
Note that expected units for bands are micrometers.
'''
from spectral.algorithms.resampling import BandResampler
from spectral.io.envi import SpectralLibrary
import numpy
import unicodedata
spectra = numpy.empty((len(spectrumIDs), len(bandInfo.centers)))
cursor = self.cursor.execute(
'''
SELECT a.ValuesArray, b.ValuesArray, a.Description, b.Unit
FROM Samples AS a INNER JOIN SpectrometerData AS b
ON a.AssumedWLSpmeterDataID = b.SpectrometerDataID
WHERE a.SampleID IN ({})'''.format(
','.join(['?'] * len(spectrumIDs))), spectrumIDs)
names = []
for i, s in enumerate(cursor):
y = array_from_blob(s[0])
x = array_from_blob(s[1])
name = s[2]
unit = s[3]
if unit == 'nanometers':
x /= 1000
resample = BandResampler(x, bandInfo.centers, None,
bandInfo.bandwidths)
spectra[i] = resample(y)
names.append(
unicodedata.normalize('NFKD', name).encode('ascii', 'ignore'))
header = {}
header['wavelength units'] = 'um'
header['spectra names'] = names
header['wavelength'] = bandInfo.centers
header['fwhm'] = bandInfo.bandwidths
return SpectralLibrary(spectra, header, {})
def create_envi_spectral_library(self, spectrumIDs, bandInfo):
'''Creates an ENVI-formatted spectral library for a list of spectra.
Arguments:
`spectrumIDs` (list of ints):
List of **SpectrumID** values for of spectra in the "Spectra"
table of the ASTER database.
`bandInfo` (:class:`~spectral.BandInfo`):
The spectral bands to which the original ASTER library spectra
will be resampled.
Returns:
A :class:`~spectral.io.envi.SpectralLibrary` object.
The IDs passed to the method should correspond to the SpectrumID field
of the ASTER database "Spectra" table. All specified spectra will be
resampled to the same discretization specified by the bandInfo
parameter. See :class:`spectral.BandResampler` for details on the
resampling method used.
'''
from spectral.algorithms.resampling import BandResampler
from spectral.io.envi import SpectralLibrary
import numpy
import unicodedata
spectra = numpy.empty((len(spectrumIDs), len(bandInfo.centers)))
names = []
for i in range(len(spectrumIDs)):
sig = self.get_signature(spectrumIDs[i])
resample = BandResampler(sig.x, bandInfo.centers, None,
bandInfo.bandwidths)
spectra[i] = resample(sig.y)
names.append(
unicodedata.normalize('NFKD', sig.sample_name).encode(
'ascii', 'ignore'))
header = {}
header['wavelength units'] = 'um'
header['spectra names'] = names
header['wavelength'] = bandInfo.centers
header['fwhm'] = bandInfo.bandwidths
return SpectralLibrary(spectra, header, {})