GEOMETRIC PARAMETERS
DATE AND TIME: The time of the AVIRIS overflight in GMT
Enter the DATE in the format DD-MM-YYYY
where DD is the day (1-31)
MM is the month (1-12)
YYYY is the year (>1986)
Enter the TIME in the format HH:MM:SS
where HH is the hour (0-23)
MM is the minutes (0-59)
SS is the seconds (0-59)
LATITUDE AND LONGITUDE: The latitude and longitude of the center of the image
Enter the LATITUDE in the format DD’MM’SS and choose the hemisphere
where DD is the degrees (0-89) N is North
MM is the minutes (0-59) S is South
SS is the seconds (0-59)
Enter the LONGITUDE in the format DD’MM’SS and choose the hemisphere
where DD is the degrees (0-179) E is East
MM is the minutes (0-59) W is West
SS is the seconds (0-59)
SPECTRAL PARAMTERS
SPECTRAL RESOLUTION: Average Spectral Resolution of the AVIRIS image
Enter the SPECTRAL RESOLUTION in the range of 8 to 20 nm.
* You may enter 0 if you want to use the full-width half-maximum
(FWHM) values for each channel. This value will be read from
the FWHM file specified.
WAVELENGTH FILE: The name of the AVIRIS wavelength file associated with
AVIRIS image data being processed
Enter the path and name of the wavelength and FWHM information file.
* This file has 3 columns:
(1) channel number
(2) Channel center wavelengths in micrometers
(3) Channel FWHM values
* This file may need to be created from the Spectral Calibration
file provided by JPL with the AVIRIS image
CHANNEL RATIO: Removes the effects of the linear variation, due to water
vapour, of surface reflectance with wavelength and gives the
transmittances of the absorption channel.
Select DEFAULT for the program default values or Select USER-DEFINED
to define your own parameters for both the 0.94 um and 1.14 um water
absorption bands. (Atmospheric windows are wavelength ranges where the
atmosphere is particularly transmissive of energy.)
USER-DEFINED values are imputed as follows:
(1) center wavelength for the first atmospheric window
(2) number of narrow AVIRIS channels to average in the first
atmospheric window to form a broad window channel
(3) center wavelength for the second atmospheric window
(4) number of narrow AVIRIS channels to average in the second
atmospheric window to form a broad window channel
(5) the center wavelength for the water vapour absorption band
(6) the number of narrow AVIRIS channels to average to form a
broad water vapour absorption channel
Example> 0.94 um water vapour band: 0.865 3 1.025 3 0.945 5
1.14 um water vapour band: 1.050 3 1.230 3 1.140 5
ATMOSPHERIC PARAMTERS
ATMOSPHERIC MODEL: The model chosen should describe the atmospheric conditions
at the time of the AVIRIS overflight.
Select one of the MODELS listed for the conditions of the AVIRIS flight:
– TROPICAL
– MID-LATITUDE SUMMER
– MID-LATITUDE WINTER
– SUBARCTIC SUMMER
– SUBARCTIV WINTER
– US STANDARDD 1962
– USER-DEFINED MODEL
If you chose USER-DEFINED MODEL, you must supply the information based on
the atmospheric conditions during the AVIRIS overflight. Your user-defined
atmospheric model may be obtained from Radiosonde flights, other atmosphere
layer sampling experiments, or your own or others model of the atmosphere.
The information will be supplied in the form of a file provided by you.
The file will contain the following information:
1 number of boundaries being used
2 altitude in kilometres
3 pressure in atmospheres
4 temperature in Kelvin
5 volume mixing ratio in parts per million
This information will be in column format for each layer
GAS SELECTORS: These are the indicators for determining which of the seven
gases that have absorption features in the 0.4-2.5um range
that you want to include in the atmospheric gaseous transmission
calculations.
The seven gases are: water vapour, carbon dioxide, ozone, nitrous oxide,
carbon monoxide, methane, and oxygen.
TOTAL OZONE: Specifies the vertical column amount of ozone (atm-cm) that is
contained in the atmosphere. This is used for the ozone
transmittance calculations.
Enter the TOTAL vertical column amount of OZONE in the atmosphere (atm-cm)
The valid range is 0.1 – 0.6 atm-cm.
A typical column ozone amount is 0.34 atm-cm
AEROSOL MODEL AND VISIBILITY (or OPTICAL DEPTH AT 0.55 um)
Specifies the aerosol conditions and visibility, or optical depth
at 550nm, at time of AVIRIS flight.
0 – no aerosol
1 – continental aerosol
2 – maritime aerosol
3 – urban aerosol
visibility: 0 – 300 km
optical depth: 0.0 – 10.0
AVERAGE ELEVATION: This value is the average elevation of the scene (in units
of kilometres). It is used to re-define the lower boundary
of an atmospheric model. The surface elevation can be
greater than the altitude of the bottom layer boundary of
the selected atmospheric model.
Valid Values are between 0 and 10 km
INPUT FILE PARAMETERS
INPUT AVIRIS IMAGE: The AVIRIS image file will be the scaled radiometrically
calibrated AVIRIS data provided by JPL (information for
obtaining such files is located on their website at
http://makalu.jpl.nasa.gov/). The image format of the
AVIRIS data file is an optional header, then the image
data in either band sequential (BSQ), band interleaved
by pixel (BIP), or band interleaved by line (BIL) format.
The imaging data must be 2-byte integers in the local
machine’s byte order (JPL distributes the data in the Sun
system’s byte order).
Enter a valid unix path and the filename of the AVIRIS data file.
HEADER INFORMATION: This button allows the user to select to input the header
and image specifications rather than let the program either
read the valid SIPS header from the data file or use default
values (0 byte header, 614 samples, 512 lines, 224 band,
BIL storage order).
If you select HEADER INFORMATION
Enter the dimensions of the header, in bytes
the number of samples per line
the number of lines per band
the number of bands
and select the storage order, BSQ Band Sequential
BIP Band interleaved by pixel
BIL Band interleaved by line
OUTPUT FILE PARAMETERS
OUTPUT: This selection chooses whether to write the output image data to file
or to memory
If you select FILE, you must provide the file names to which you want
the data to be written.
REFLECTANCE FILE: Enter the path and filename of the file to save the
true ground reflectance data image.
WATER VAPOR FILE: Enter the path and filename of the file to save the
water vapour data image
TRANS. SPECTRA FILE: This is a library file containing the output transmission
library file. The file contains 60 water vapour values.
Associated with each water vapour value are the channel
ratio values for the 0.94 and the 1.14 um water vapour
bands and an atmospheric gas transmittance spectrum at
AVIRIS wavelength positions and spectral resolution.
The first line of the file has 10 column water vapour values, the second
line has 10 ratio values for the 0.94 um region, and the third line has 10
ratio values for the 1.14um region. The next lines (usually 224) contain
wavelengths in the first column and 10 transmittance spectra in the rest of
the columns. The 10 spectra correspond to the water vapour values in the
first line. There are a total of 6 groups of 10 sets of data. An example
of the first group of data (showing only 4 of the 10 transmittance
spectra:
0.0000E+00 0.4161E-01 0.1248E+00 0.2288E+00 <– water vapour values
0.1000E+01 0.9679E+00 0.9279E+00 0.8926E+00 <– ratios for 0.94um region
0.1001E+01 0.9297E+00 0.8594E+00 0.8036E+00 <– ratios for 1.14um region
0.3734 0.1000E+01 0.1000E+01 0.1000E+01 0.1000E+01 <– wavelength and
0.3829 0.1000E+01 0.1000E+01 0.1000E+01 0.1000E+01 transmittance spectra
0.3925 0.1000E+01 0.1000E+01 0.1000E+01 0.1000E+01
0.4021 0.1000E+01 0.1000E+01 0.1000E+01 0.1000E+01
0.4117 0.1000E+01 0.1000E+01 0.1000E+01 0.1000E+01
0.4214 0.1000E+01 0.1000E+01 0.1000E+01 0.1000E+01
: :
: :
2.4738 0.9980E+00 0.9387E+00 0.8897E+00 0.8517E+00
2.4836 0.9983E+00 0.9144E+00 0.8439E+00 0.7888E+00
2.4934 0.9986E+00 0.9055E+00 0.8288E+00 0.7691E+00
2.5033 0.9988E+00 0.9063E+00 0.8278E+00 0.7671E+00
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