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| Batch Mode | Yes |
| Quick links | Description :: Parameters :: Parameter descriptions :: Details :: Acknowledgements :: References :: Related |
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Tape5 MODTRAN4 File
Specifies the name of the output MODTRAN4 "tape5" file to be created.
If no leading path is specified, the file will be created in the current working directory.
Atmospheric Model
Specifies the type of atmospheric model used to evaluate the MODTRAN4 CARD 1 "MODEL" column.
Water Vapor Content Interval
Specifies the atmospheric water vapor content interval endpoints (in g/cm^2). An endpoint value e must be such that e >= 0. This value modifies the selected atmospheric model used to evaluate the MODTRAN4 CARD 1A "H2OSTR" column.
If this parameter is not specified, the "tape 5" file will represent a single water vapor content sample for which the value is the default value for the selected atmospheric model.
Water Vapor Content Samples
Specifies the number of atmospheric water vapor content samples.
If this parameter is not specified, the "tape 5" file will represent a single water vapor content sample for which the value is the default value for the selected atmospheric model.
Multiple Scattering Algorithm
Specifies the multiple scattering sub-algorithm used to evaluate the MODTRAN4 CARD 1A "DIS" column.
Number of Streams for DISORT
Specifies the number of streams to be used by the discrete ordinates radiative transfer sub-algorithm. This value is used to evaluate the MODTRAN4 CARD 1A "NSTR" column. If the Multiple Scattering Algorithm is not specified as "DISTORT", this parameter is ignored.
A value of 2, 4, 8, or 16 may be specified; the default is 2. Higher values result in longer computation time.
Aerosol Model
Specifies the type of aerosol model used for boundary layer (0 to 2km) calculations. This value is used to evaluate the MODTRAN4 CARD 2 "IHAZE" column.
If the surface meteorological range (SMRINS) is not specified, the "tape5" file will represent a single-surface meteorological range sample for which the value is the default value for the aerosol model.
Aerosol Optical Depth Range Interval
Specifies the aerosol optical depth range interval at 550nm endpoints (unitless) and the number of samples. An endpoint value e must be such that 0 <= e <= 2.
The Aerosol Optical Depth Range (interval and samples) parameters are used as an alternative to the Surface Meteorological Range parameters (interval and samples) for evaluating the MODTRAN4 CARD 2 "VIS" column; only one these two parameter sets may be specified.
If neither the Aerosol Optical Depth Range nor the Surface Meteorological Range is specified, the "tape5" file will represent a single-surface meteorological range sample for which the value is the default value for the aerosol model.
Aerosol Optical Depth Range Samples
Specifies the number of aerosol optical depth range samples.
The Aerosol Optical Depth Range (interval and samples) parameters are used as an alternative to the Surface Meteorological Range parameters (interval and samples) for evaluating the MODTRAN4 CARD 2 "VIS" column; only one these two parameter sets may be specified.
If neither the Aerosol Optical Depth Range nor the Surface Meteorological Range is specified, the "tape5" file will represent a single-surface meteorological range sample for which the value is the default value for the aerosol model.
Surface Meteorological Range Interval
Specifies the surface meteorological range interval endpoints (in km) and the number of samples. An endpoint value e must be such that 0 < e.
The Surface Meteorological Range parameters (interval and samples) are used as an alternative to the Aerosol Optical Depth Range (interval and samples) parameters for evaluating the MODTRAN4 CARD 2 "VIS" column; only one these two parameter sets may be specified.
If neither the Aerosol Optical Depth Range nor the Surface Meteorological Range is specified, the "tape5" file will represent a single-surface meteorological range sample for which the value is the default value for the aerosol model.
Surface Meteorological Range Samples
Specifies the number of surface meteorological range samples.
The Surface Meteorological Range parameters (interval and samples) are used as an alternative to the Aerosol Optical Depth Range (interval and samples) parameters for evaluating the MODTRAN4 CARD 2 "VIS" column; only one these two parameter sets may be specified.
If neither the Aerosol Optical Depth Range nor the Surface Meteorological Range is specified, the "tape5" file will represent a single-surface meteorological range sample for which the value is the default value for the aerosol model.
Aerosol Stratospheric Profile and Extinction Type
Specifies the aerosol profile and stratospheric aerosol extinction types. Modifies the selected aerosol model.
This value is used to evaluate the MODTRAN4 CARD 2 "IVULCN" column. If not specified, the "background" stratospheric profile and extinction type is used.
Wavelength Interval
Specifies the wavelength interval endpoints (in nanometers).
An endpoint value e must be such that e >200nm. This value is used to evaluate the MODTRAN4 CARD 4 "V1", "V2", and "DV" columns.
Wavelength Samples
Specifies the number of wavelength samples.
Reflectance Interval
Specifies the reflectance interval endpoints (in percentage).
An endpoint value e must be such that 0 < e <= 1. This value is used to evaluate the MODTRAN4 CARD 1 "SURREF" column.
Reflectance Samples
Specifies the number of reflectance samples.
Relative View-Solar Azimuth Interval
Specifies the relative view-solar azimuth (solar azimuth minus view azimuth) interval endpoints (in degrees).
An endpoint value e must be such that -360 <= e <= 360. This value is used to evaluate the MODTRAN4 CARD 3A2 "PARM1" column.
Relative View-Solar Azimuth Samples
Specifies the number of relative view-solar azimuth (solar azimuth minus view azimuth) samples.
View Zenith Angle Interval
Specifies the view zenith angle interval endpoints (in degrees).
An endpoint value e must be such that 90 <= e <= 180. This value is used to evaluate the MODTRAN4 CARD 3 "ANGLE" column. A horizontal view direction has a zenith angle of 90deg, and a vertical down view direction has a zenith angle of 180deg.
View Zenith Angle Samples
Specifies the number of view zenith angle samples.
Solar Zenith Angle Interval
Specifies the solar zenith angle interval endpoints (in degrees).
An endpoint value e must be such that 0 <= e <= 90. This value is used to evaluate the MODTRAN4 CARD 3A2 "PARM2" column.
Solar Zenith Angle Samples
Specifies the number of solar zenith angle samples.
Scene Elevation Interval
Specifies the scene elevation interval endpoints (in meters with respect to the WGS84 vertical datum).
This value is used to evaluate the MODTRAN4 CARD 3 "H2" and CARD 2 "GNDALT" columns.
Scene Elevation Samples
Specifies the number of scene elevation samples.
Sensor Altitude Interval
Specifies the sensor altitude interval endpoints (in meters with respect to the WGS84 vertical datum).
This value is used to evaluate the MODTRAN4 CARD 3 "H1" column.
Sensor Altitude Samples
Specifies the number of sensor altitude samples.
Date of the Scene
Specifies the date (day, month, year) that MODTRAN4 will use to calculate the sun-to-Earth distance. If this parameter is not specified, a mean sun-to-Earth distance will be used instead, equivalent to using the 3rd of April (in non-leap years) as the date. The year component of the date may be omitted.
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GENTP5 is designed to be used in combination with the MODTRAN4 program and GENRLUT to produce a radiance lookup table (RLUT) for the atmospheric transformation of remotely sensed images. GENTP5 has been tested with Versions 2 and 3 of the MODTRAN4 program.
The "tape5" file generated by GENTP5 holds input parameter values (sets of "cards" in MODTRAN terms) for one or more MODTRAN4 runs. Multiple MODTRAN4 runs correspond to multiple samples along one or more RLUT dimensions other than the wavelength dimension. The multiple MODTRAN4 runs are actually made in one execution of the the MODTRAN4 program.
The "tape7" file generated by the MODTRAN4 program contains the results of the MODTRAN4 runs. GENRLUT transforms this file to an RLUT.
GENTP5 provides two ways of specifying the MODTRAN4 CARD 2 "VIS" parameter: by using an aerosol optical depth and by using a surface meteorological range. As those two parameters affect the same MODTRAN4 setting, only one of them may be specified for a GENTP5 execution. If you denote the surface meteorological range with VIS and the aerosol optical depth with AOD, the AOD-to-VIS mapping is accomplished using the following third-order polynomial approximation:
1/VIS = -0.014267*AOD^3 + 0.062699*AOD^2 + 0.117591*AOD - 0.001074
GENTP5 does not give the user access to all of the MODTRAN4 parameters and options; only those that match a practical atmospheric correction method are accessible. There is no dependence on difficult-to-obtain field measurements. Also, GENTP5 makes some choices to avoid extra computation that would contribute little to the usefulness of the RLUT generated by GENRLUT.
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PCI Geomatics received financial support from the Canadian Space Agency/L'Agence Spatiale Canadienne through the Earth Observation Application Development Program (EOADP) for the development of this software, under contract 9F028-0-4914/09.
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R.A. Neville et al., Spectral Unmixing of Hyperspectral Imagery for Mineral Exploration: Comparison of Results from SFSI and AVIRIS, "Can. J. Remote Sensing," Vol.29, No.1, pp. 99-110, 2003.
Berk, A. et al., 1999, "Modtran4 User's Manual", Air Force Research Laboratory, Space Vehicles Directorate, Air Force Materiel Command, Hanscom AFB, MA
Matthew, M.W. et al. "Status of Atmospheric Correction Using a Modtran4-Based Algorithm", SPIE Proceeding, Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI, Volume 4049, April 2000.
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