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'''
Functions for handling AVIRIS image files.
'''
from __future__ import absolute_import, division, print_function, unicode_literals
import numpy as np
import glob
import os
import spectral as spy
from ..spectral import BandInfo
from ..utilities.python23 import IS_PYTHON3
from .bipfile import BipFile
from .spyfile import find_file_path, InvalidFileError
if IS_PYTHON3:
import builtins
else:
import __builtin__ as builtins
def open(file, band_file=None):
'''
Returns a SpyFile object for an AVIRIS image file.
Arguments:
`file` (str):
Name of the AVIRIS data file.
`band_file` (str):
Optional name of the AVIRIS spectral calibration file.
Returns:
A SpyFile object for the image file.
Raises:
spectral.io.spyfile.InvalidFileError
'''
class Params:
pass
p = Params()
p.filename = find_file_path(file)
p.nbands = 224
p.ncols = 614
fileSize = os.stat(p.filename)[6]
if fileSize % 275072 != 0:
raise InvalidFileError('File size not consistent with AVIRIS format.')
p.nrows = int(fileSize / 275072)
p.byte_order = 1
p.dtype = np.dtype('i2').str
if spy.byte_order != 1:
p.dtype = np.dtype(p.dtype).newbyteorder().str
metadata = {'default bands': ['29', '18', '8']}
p.offset = 0
img = BipFile(p, metadata)
img.scale_factor = 10000.0
if band_file:
img.bands = read_aviris_bands(find_file_path(band_file))
return img
def read_aviris_bands(cal_filename):
'''
Returns a BandInfo object for an AVIRIS spectral calibration file.
Arguments:
`cal_filename` (str):
Name of the AVIRIS spectral calibration file.
Returns:
A :class:`spectral.BandInfo` object
'''
bands = BandInfo()
bands.band_quantity = 'Wavelength'
bands.band_unit = 'nm'
fin = builtins.open(find_file_path(cal_filename))
rows = [line.split() for line in fin]
rows = [[float(x) for x in row] for row in rows if len(row) == 5]
columns = list(zip(*rows))
bands.centers = columns[0]
bands.bandwidths = columns[1]
bands.center_stdevs = columns[2]
bands.bandwidth_stdevs = columns[3]
bands.band_unit = 'nm'
return bands
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