Home
About ISIS
Support
Download

ISIS 3

Documentation
Tutorials
Technical Documents

ISIS 2

Documentation
Tutorials
Technical Documents
USGS

ISIS 3 Application Documentation

photemplate

Printer Friendly View | TOC | Home

Create a PVL template for photometric correction

Overview Parameters Example 1

Description

This program creates a PVL template file to be used in photometry-based applications, such as photomet. Each planet has different surface and atmospheric properties requiring different model specifications. It is important to set up the models with unique parameter values that apply to a specific planetary body. There are two types of correction models that can be specified in this program:

  1. Photometric - describes the planetary surface of an image
  2. Atmospheric - applies to the atmosphere through which an image was acquired

The normalization models are not specified in this program, but only three models (albedoatm, shadeatm, and topoatm) apply atmosperheric correction. Choose an atmospheric model only if one of the three normalization models listed above will be applied with the photomet program.

This program allows the use of a PVL file that contains preset parameter names for different photometric and atmospheric models. NOTE: if the user leaves the ZEROB0STANDARD parameter set to READFROMPVL and does not provide an input PVL file, then the ZEROB0STANDARD parameter will default to TRUE. Within the GUI, the user may select a PVL file and then use the drop-down menu to view the contents of the PVL file or to load the parameter values from the PVL file into the appropriate parameter names in the GUI. Note: If more than one model for "PhtName" or "AtmName" are in the PVL file, then the parameter values for the first model type encountered by the program will be loaded into the GUI. Review the parameter names and values to make sure the correct options and values are displayed before executing the program. Below are examples of parameter settings within a PVL file: 

PVL file examples: 
     
  Example 1:				Example 2:		  

  Object = PhotometricModel		Object = PhotometricModel
   Group = Algorithm			  Group = Algorithm
      PhtName = Lambert 		    PhtName = Minnaert
    EndGroup				    K = 0.5
  EndObject				  EndGroup
					EndObject
  
	
  Example 3:				Example 4:		     
  
  Object = PhotometricModel		Object = PhotometricModel
    Group  = Algorithm  		  Group  = Algorithm
      PhtName = Hapkehen  		    PhtName = Lunarlambertmcewen
      Wh = 0.52 			  EndGroup
      Hh = 0.0  			EndObject
      B0 = 0.0
      Theta = 30.0
      Hg1 = 0.213
      Hg2 = 1.0
    EndGroup
  EndObject
  Object = AtmosphericModel
    Group = Algorithm
      AtmName = Hapkeatm2
      Hnorm = 0.003
      Tau = 0.28
      Tauref = 0.0
      Wha = 0.95
      Hga = 0.68
    EndGroup
  EndObject
  
  Example 5:
       
  Object = PhotometricModel
  # For Mars red filter images
  # The phase angles at which the coefficient values for the Lunar Lambert 
  # Empirical L and the Minnaert Empirical K approximation are 
  # calculated, along with the brightness (phase curve) values at those
  # points (ALL ON ONE LINE!)

    Group = Algorithm
      PhtName = LunarLambertEmpirical
      PhaseList = "0.,10.,20.,30.,40.,50.,60.,70.,80.,90.,100.,110.,120.,130.,
                  140.,150.,160.,170.,180."
      LList = "0.946,0.748,0.616,0.522,0.435,0.350,0.266,0.187,0.118,0.062,0.018,
              -0.012,-0.027,-0.035,-0.036,-0.037,-0.031,-0.012,-0.010"
      PhaseCurveList = "0.1578,0.1593,0.1558,0.1484,0.1391,0.1292,0.1194,0.1099,
                       0.1008,0.09176,0.08242,0.07234,0.06165,0.05106,0.04091,
		       0.03137,0.02171,0.01038,0."
    EndGroup

    Group = Algorithm
      PhtName = MinnaertEmpirical
      
      # The numbers below are entered on a single line in the text file for each
      # parameter name (see $ISIS3DATA/base/templates/photometry/marsred.pvl).
      
      PhaseList = "0.,10.,20.,30.,40.,50.,60.,70.,80.,90.,100.,110.,120.,130.,
                  140.,150.,160.,170.,180."
      KList = "0.518,0.595,0.660,0.709,0.753,0.796,0.837,0.875,0.904,0.922,
              0.926,0.935,0.954,0.986,1.019,1.063,1.099,1.095,1.090"
      PhaseCurveList = "0.1574,0.1582,0.1546,0.1470,0.1375,0.1273,0.1174,0.1077,
                       0.09797,0.08750,0.07594,0.06466,0.05471,0.04665,0.03935,
		       0.03339,0.02642,0.01482,0."
    EndGroup
  EndObject

Below are equations for some of the photometric model functions, where phase is the phase angle, and u0 and u are the cosines of the incidence angle and emission angle, respectively:

SURFACE PHOTOMETRIC FUNCTION


Available photometric models and equations
Photometric Model Name Function Equation
Lambert u0
LommelSeeliger u0/(u0+u)
Minnaert u0**K * u**(K-1)
LunarLambert ("lunar" part is Lommel-Seeliger) (1-L)*u0 + 2*L*u0/(u0+u)
MinnaertEmpirical B(phase) * u0**K(phase) * u**(K(phase)-1)
LunarLambertEmpirical B(phase) * ((1-L)*u0 + 2*L*u0/(u0+u))
Hapkehen (Hapke-Henyey-Greenstein) No equation available
Hapkeleg (Hapke-Legendre) No equation available
LunarLambertMcEwen No equation available 
References:

Chandrasekhar, S., 1960.  Radiative Transfer. Dover, 393 pp.
Hapke, B. W., 1981. Bidirectional reflectance spectroscopy 1: Theory. J. 
   Geophys. Res., pp. 86,3039-3054.
Hapke, B., 1984. Bidirectional reflectance spectroscopy3: Corrections for 
   macroscopic roughness. Icarus, 59, pp. 41-59.
Hapke, B., 1986. Bidirectional reflectance spectroscopy 4: The extinction 
   coefficient and the opposition effect. Icarus, 67, pp. 264-280.
Kirk, R. L., Thompson, K. T., Becker, T. L., and Lee, E. M., 2000. 
   Photometric modelling for planetary cartography. Lunar Planet. Sci., XXXI, 
   Abstract #2025, Lunar and Planetary Institute, Houston (CD-ROM).

See photomet documetation for additional information.

Categories

Related Objects and Documents

Applications

History

Noah Hilt2008-11-18 Original version.
Janet Barrett2011-09-23 1) The entire user interface has been redesigned. The previous version of this program made use of radio button lists to allow the user to choose a photometric model or an atmospheric model. In order to make the program more compact, the radio button lists were replaced with drop down menus. When an option is chosen from the drop down menu, the parameters that apply to that option are made visible. Parameters that don't apply to that option remain hidden. This helps to make the interface look less cluttered than it did when every parameter and every option were visible all the time. 2) The "NORMALIZATION" option is no longer available in this program. This program's main use is to create files with preset photometric and atmospheric values for use with various planets. The normalization models are not specific to individual planets like the atmospheric and photometric models are. The normalization mode is only used in the photomet program, so this information now needs to be provided through photomet. 3) The PVL parameter was replaced with the TOPVL parameter. The PHOTOMETRIC parameter was replaced with PHTNAME. The ATMOSPHERIC parameter was replaced with ATMNAME. 4) The BHAREF, HGAREF, and WHAREF parameters were removed because they have become obsolete. 5) The Hapke Legendre (HAPKELEG), empirical Minnaert (MINNAERTEMPIRICAL), and empirical Lunar Lambert (LUNARLAMBERTEMPIRICAL) photometric functions have been added. 6) Documentation describing the parameters is still central to the photomet program. The documentation will be moved into this program in the next ISIS release. 7) Helper buttons were added to the FROMPVL to allow you to View a PVL or to Load a PVL. PLEASE NOTE: When loading a Minnaert Empirical or Lunar Lambert Empirical model from a PVL, only the first value will be loaded into the GUI. This is a known problem and will be fixed in the next patch or release to ISIS. 8) ***NOTE*** The Minnaert Empirical and Lunar Lambert Empirical models do not load properly from a PVL file when using the Load Pvl helper button. This is a known problem and will be fixed in the next patch or release of ISIS.
Sharmila Prasad2011-10-27 Added API's to display and output PVL information, specifically for arrays and alphabetically organized the Photometric Model names.
Ella Mae Lee2012-11-16 Improved the documentation, fixes #452.
Lynn Weller2013-02-25 Removed links to applications imbedded in text and replaced with italicized application name. Added application links to the "Related Objects and Documents" section of the documentation. Fixes mantis ticket #1525.

Parameter Groups

Files

Name Description
FROMPVL Input PVL file with photometric parameters
TOPVL Output PVL file containing the photometric parameter values

Photometric Parameters

Name Description
PHTNAME Photometric model to be used
THETA Macroscopic roughness angle
WH Single scattering albedo
HG1 Hapke Henyey Greenstein coefficient
HG2 Hapke Henyey Greenstein coefficient
BH The Hapke Legendre coefficient for single particle phase function.
CH Hapke Legendre coefficient
HH Hapke opposition surge
B0 Hapke opposition surge
ZEROB0STANDARD Specifies if opposition surge is set to zero under standard conditions
L Lunar-Lambert function weight
K Minnaert function exponent
PHASELIST Empirical functions phase angle list
KLIST Minnaert Empirical function limb darkening parameter list
LLIST The Lunar Lambert Empirical function limb darkening parameter list
PHASECURVELIST Empirical functions phase curve (brightness) value list

Atmospheric Parameters

Name Description
ATMNAME Atmospheric model to be used
NULNEG Specifies if negative values will be set to NULL
TAU Optical depth of atmosphere
TAUREF Reference value of tau
HGA Henyey Greenstein coefficient
WHA Single scattering albedo
BHA Legendre coefficient
HNORM Atmospheric shell thickness
X

Files: FROMPVL

Description

Use this parameter to select an existing PVL filename that contains a description of the photometric properties of a planetary body. The information in this file will be merged with the information that is input through the user interface or command line to create the output PVL file.

Type filename
File Mode input
Default Path $base/templates/photometry
Internal Default None Specified
Filter *.pvl
Close Window
X

Files: TOPVL

Description

Use this parameter to select or enter the output filename. If the file already exists it will be overwritten. The ".pvl" extension is automatically appended to the filename if no extension is entered.

Type filename
File Mode output
Filter *.pvl
Close Window
X

Photometric Parameters: PHTNAME

Description

This is the name of the surface photometric function model to use to apply the photometric correction. Both the abbreviated names and the full model names are valid entries.

Type combo
Default FROMPVL
Internal Default FROMPVL
Option List:
Option Brief Description
FROMPVLGet photometric model from PVL file Get the photometric model from the PVL file. Add any missing parameters to the PVL file, or enter the values on the command line or use the GUI to enter the values.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • HH
  • B0
  • BH
  • CH
  • L
  • K
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST
  • ZEROB0STANDARD
HAPKEHEN Hapke-Henyey-Greenstein photometric model Derive model albedo using complete Hapke model with Henyey-Greenstein single-particle phase function whose coefficients are hg1 and hg2, plus single scattering albedo wh, opposition surge parameters hh and b0, and macroscopic roughness theta. For a smooth model with opposition effect use theta=0.

Exclusions

  • BH
  • CH
  • L
  • K
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST

Inclusions

  • THETA
  • WH
  • HG1
  • HG2
  • HH
  • B0
HAPKELEG Hapke-Legendre photometric model Derive model albedo using complete Hapke model with Henyey Legendre two-term Legendre polynomial phase function whose coefficients are bh and ch, plus single scattering albedo wh, opposition surge parameters hh and b0, and macroscopic roughness theta.

Exclusions

  • HG1
  • HG2
  • L
  • K
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST

Inclusions

  • THETA
  • WH
  • BH
  • CH
  • HH
  • B0
LAMBERT Lambert photometric model Simple photometric model which predicts that light incident on a surface is scattered uniformly in all directions; the total amount of reflected light depends on the incidence angle of the illumination. This function does not depend upon the outgoing light direction.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • HH
  • B0
  • BH
  • CH
  • L
  • K
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST
LOMMELSEELIGER Lommel-Seeliger photometric model This model takes into account the radiance that results from single scattering (scattering of collimated incident light) and does not take into account the radiance that results from multiple scattering (scattering of diffuse light which has made its way indirectly to the same position by being scattered one or more times). This model depends on the incidence and emission angles.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • BH
  • CH
  • HH
  • B0
  • L
  • K
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST
LUNARLAMBERT Lunar Lambert photometric model This model combines a weighted sum of the LommelSeeliger and Lambert models. Given a suitable value for the LunarLambert function weight, L, this model fits the true reflectance behavior of many planetary surfaces equally well as the Hapke model. This model also depends on the incidence and emission angles.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • BH
  • CH
  • HH
  • B0
  • K
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST

Inclusions

  • L
LUNARLAMBERTEMPIRICAL Lunar Lambert Empirical photometric model This model combines a weighted sum of the LommelSeeliger and Lambert models. Given a suitable value for the LunarLambert function weight, L, this model fits the true reflectance behavior of many planetary surfaces equally well as the Hapke model. This model also depends on the incidence and emission angles.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • BH
  • CH
  • HH
  • B0
  • K
  • L
  • KLIST

Inclusions

  • PHASELIST
  • LLIST
  • PHASECURVELIST
LUNARLAMBERTMCEWEN Lunar Lambert-McEwen photometric model This model was developed specifically for use with the Moon to be used in conjunction with the MoonAlbedo normalization model.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • BH
  • CH
  • HH
  • B0
  • L
  • K
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST
MINNAERT Minnaert photometric model This model combines a weighted sum of the LommelSeeliger and Lambert models. Given a suitable value for the LunarLambert function weight, L, this model fits the true reflectance behavior of many planetary surfaces equally well as the Hapke model. This model also depends on the incidence and emission angles.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • BH
  • CH
  • HH
  • B0
  • L
  • PHASELIST
  • KLIST
  • LLIST
  • PHASECURVELIST

Inclusions

  • K
MINNAERTEMPIRICAL Minnaert Empirical photometric model This model combines a weighted sum of the LommelSeeliger and Lambert models. Given a suitable value for the LunarLambert function weight, L, this model fits the true reflectance behavior of many planetary surfaces equally well as the Hapke model. This model also depends on the incidence and emission angles.

Exclusions

  • THETA
  • WH
  • HG1
  • HG2
  • BH
  • CH
  • HH
  • B0
  • K
  • L
  • LLIST

Inclusions

  • PHASELIST
  • KLIST
  • PHASECURVELIST
Close Window
X

Photometric Parameters: THETA

Description

The "macroscopic roughness" of the surface as it affects the photometric behavior, used for Hapkehen or Hapkeleg. This is the RMS slope at scales larger than the distance photons penetrate the surface but smaller than a pixel. The roughness correction, which will be evaluated if theta is given any value other than 0.0, but is extremely slow. See Hapke (1986).

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Maximum 90.0 (inclusive)
Close Window
X

Photometric Parameters: WH

Description

The Hapke single scattering albedo of surface particles, see Hapke (1981).

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (exclusive)
Maximum 1.0 (inclusive)
Close Window
X

Photometric Parameters: HG1

Description

Asymmetry parameter used in Hapke Henyey Greenstein model for the scattering phase function of single particles in the surface. See Hapke (1981). The two-parameter Henyey Greenstein function is:

P(phase)=(1-hg2) * (1-hg1**2)/(1+hg1**2+2*hg1*cos(phase))**1.5 + hg2 * (1-hg1**2)/(1+hg1**2-2*hg1*cos(phase))**1.5

Type string
Default None Specified
Internal Default None Specified
Minimum -1.0 (exclusive)
Maximum 1.0 (exclusive)
Close Window
X

Photometric Parameters: HG2

Description

The Hapke Henyey Greenstein coefficient for single particle phase function. Second parameter of the two-parameter Henyey-Greenstein model for the scattering phase function of single particles in the surface. This parameter controls the proportions in a linear mixture of ordinary Heneyey Greenstein phase functions with asymmetry parameters equal to +hg1 and -hg1. See HG1 for the full formula.

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Maximum 1.0 (inclusive)
Close Window
X

Photometric Parameters: BH

Description

The Hapke Legendre coefficient for single particle phase function. A two-term Legendre polynomial is used for the scattering phase function of single particles in the surface:

P(phase) = 1 + bh * p1(cos(phase)) + ch * p2(cos(phase))
Bh is not to be confused with the legendre coefficient bha of the phase function for atmospheric particles, used when atmname=anisotropic1 or anisotropic2.

Type string
Default None Specified
Internal Default None Specified
Minimum -1.0 (exclusive)
Maximum 1.0 (exclusive)
Close Window
X

Photometric Parameters: CH

Description

The Hapke Legendre coefficient for single particle phase function. A two-term Legendre polynomial is used for the scattering phase function of single particles in the surface:

P(phase) = 1 + bh * p1(cos(phase)) + ch * p2(cos(phase))

Type string
Default None Specified
Internal Default None Specified
Minimum -1.0 (exclusive)
Maximum 1.0 (exclusive)
Close Window
X

Photometric Parameters: HH

Description

The Hapke opposition surge component. The width parameter for the opposition effect for the surface if Hapkehen or Hapkeleg is used. See Hapke (1984).

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Close Window
X

Photometric Parameters: B0

Description

The Hapke opposition surge component. The magnitude of the opposition effect for the surface if Hapkehen or Hapkeleg is used. See Hapke (1984).

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Close Window
X

Photometric Parameters: ZEROB0STANDARD

Description

This specifies if the opposition surge component B0 is set to zero during the standard conditions phase. NOTE: The program will automatically default to "TRUE" if "ZEROBSTANDARD" is not defined by the user.

Type string
Default TRUE
Option List:
Option Brief Description
READFROMPVL Get ZEROB0STANDARD value from the FROMPVL file Retrieve and set the ZEROB0STANDARD parameter from the FROMPVL file. If a FROMPVL file is not provided, then an error will occur. NOTE: If the user does not define a value for ZEROB0STANDARD in the input PVL file, then the ZEROB0STANDARD value will default to TRUE.
FALSE B0 will not be set to zero for standard conditions phase This option specifies that the opposition surge B0 will not be set to zero during the standard conditions phase.
TRUE B0 will be set to zero for standard conditions phase This option specifies that the opposition surge B0 will be set to zero during the standard conditions phase.
Close Window
X

Photometric Parameters: L

Description

The Lunar Lambert function weight that governs limb-darkening in the lunar lambert photometric function:

Func=(1-L)*u0 + 2*L*u0/(u0+u)
The values generally fall in the range from 0 (Lambert function) to 1 (Lommel-Seeliger or "lunar" function).

Type string
Default None Specified
Internal Default None Specified
Close Window
X

Photometric Parameters: K

Description

The Minnaert function exponent that governs limb-darkening in the Minnaert photometric function:

Func = u0**K * u**(K-1)
The values generally fall in the range from 0.5 ("lunar-like", almost no limb darkening) to 1.0 (Lambert function).

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Close Window
X

Photometric Parameters: PHASELIST

Description

The Minnaert Empirical and Lunar Lambert Empirical function phase angle list entered as a comma delimited string describing how the parameters of the empirical function vary with phase angle. See "$ISIS3DATA/base/templates/photometry/marsred.pvl" for an example.

Type string
Default No List
Internal Default No List
Close Window
X

Photometric Parameters: KLIST

Description

The Minnaert Empirical function exponent list of limb darkening values entered as a comma delimited string that describes how the parameters of the empirical function vary with phase angle. See "$ISIS3DATA/base/templates/photometry/marsred.pvl" for an example.

Type string
Default No List
Internal Default No List
Close Window
X

Photometric Parameters: LLIST

Description

The Lunar Lambert Empirical function parameter list of limb darkening values entered as a comma delimited string that describes how the parameters of the empirical function vary with phase angle. See "$ISIS3DATA/base/templates/photometry/marsred.pvl" for an example.

Type string
Default No List
Internal Default No List
Close Window
X

Photometric Parameters: PHASECURVELIST

Description

The Minnaert Empirical or Lunar Lambert Empirical function phase curve list of brightness values corresponding to a set of phase angles defined in the PHASELIST parameter. See "$ISIS3DATA/base/templates/photometry/marsred.pvl" for an example.

Type string
Default No List
Internal Default No List
Close Window
X

Atmospheric Parameters: ATMNAME

Description

This is the name of the atmospheric photometric function model to be applied. The models ending with "1" use a first order scattering approximation. Those ending with "2" use a second order scattering approximation, and are slower but more accurate than the first order scattering approximation. The atmospheric correction can be used with only three atmospheric normalization models: albedoatm, shadeatm, and topoatm. See Kirk et al. (2001).

Type combo
Default NONE
Internal Default NONE
Option List:
Option Brief Description
NONENo atmospheric model No atmospheric correction will be applied.

Exclusions

  • HNORM
  • BHA
  • TAU
  • TAUREF
  • WHA
  • HGA
  • NULNEG
ANISOTROPIC1 Anisotropic 1 atmospheric model Uses Chandrasekhar's solution for anisotropic scattering described by a one term Legendre polynomial. This model uses first order scattering approximation.

Exclusions

  • HGA

Inclusions

  • HNORM
  • BHA
  • TAU
  • TAUREF
  • WHA
ANISOTROPIC2 Anisotropic 2 atmospheric model Uses Chandrasekhar's solution for anisotropic scattering described by a one term Legendre polynomial. This model uses second order scattering approximation. It is slower but more accurate than Anisotropic1.

Exclusions

  • HGA

Inclusions

  • HNORM
  • BHA
  • TAU
  • TAUREF
  • WHA
HAPKEATM1 Hapke 1 atmospheric model Provides an approximation for strongly anisotropic scattering that is similar to Hapke's model for a planetary surface. The Chandrasekhar solution for isotropic scattering is used for the multiple scattering terms, and a correction is made to the singly scattered light for anisotropic particle phase function. A one-term Henyey Greenstein function is used. This model uses a first order scattering approximation.

Exclusions

  • BHA

Inclusions

  • HNORM
  • HGA
  • TAU
  • TAUREF
  • WHA
HAPKEATM2 Hapke 2 atmospheric model Provides an approximation for strongly anisotropic scattering that is similar to Hapke's model for a planetary surface. The Chandrasekhar solution for isotropic scattering is used for the multiple scattering terms, and a correction is made to the singly scattered light for anisotropic particle phase function. A one-term Henyey Greenstein function is used. This model uses a second order scattering approximation. It is slower but more accurate than HAPKEATM1.

Exclusions

  • BHA

Inclusions

  • HNORM
  • HGA
  • TAU
  • TAUREF
  • WHA
ISOTROPIC1 Isotropic 1 atmospheric model Uses Chandrasekhar's solution for isotropic scattering. This model uses first order scattering approximation.

Exclusions

  • HGA
  • BHA

Inclusions

  • HNORM
  • TAU
  • TAUREF
  • WHA
ISOTROPIC2 Isotropic 2 atmospheric model Uses Chandrasekhar's solution for isotropic scattering. This model uses second order scattering approximation. It is slower but more accurate than Isotropic1.

Exclusions

  • HGA
  • BHA

Inclusions

  • HNORM
  • TAU
  • TAUREF
  • WHA
Close Window
X

Atmospheric Parameters: NULNEG

Description

This specifies if negative values after removal of atmospheric effects will be set to NULL. Negative values are only generated in modes that include atmospheric correction and occur when the optical depth "tau" is overestimated, so that the atmospheric radiance subtracted from the image is brighter than the darkest observed pixels. In this case "tau" should be decreased until no negative values are present in the output file.

Type string
Default READFROMPVL
Option List:
Option Brief Description
READFROMPVL Get NULNEG value from the FROMPVL file Retrieve and set the NULNEG parameter from the FROMPVL file. An error is reported if a PVL file is not provided.
NO Do not set negative values to NULL This option specifies not to set negative values to NULL after the removal of atmospheric effects.
YES Negative values will be set to NULL This option specifies to set negative values to NULL after the removal of atmospheric effects.
Close Window
X

Atmospheric Parameters: TAU

Description

The normal optical depth of the atmosphere.

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Close Window
X

Atmospheric Parameters: TAUREF

Description

The reference value of tau to which the image will be normalized. This would normally be 0.0 unless one is interested in simulating a hazy atmosphere scene.

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Close Window
X

Atmospheric Parameters: HGA

Description

The coefficient of single particle Henyey Greenstein phase function. Henyey-Greenestein asymmetry parameter for atmospheric particle phase function, used in hapkeatm1 and hapkeatm2 atmospheric models. Not to be confused with corresponding parameter hg1 for the surface particles.

Type string
Default None Specified
Internal Default None Specified
Minimum -1.0 (exclusive)
Maximum 1.0 (exclusive)
Close Window
X

Atmospheric Parameters: WHA

Description

The single scattering albedo of atmospheric particles.

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (exclusive)
Maximum 1.0 (inclusive)
Close Window
X

Atmospheric Parameters: BHA

Description

The coefficient of the single particle Legendre phase function. Coefficient of P1 (cosine) term of atmospheric particle phase function, used in anisotropic1 and anisotropic2 atmospheric models. Not to be confused with corresponding coefficient bh for the surface particles.

Type string
Default None Specified
Internal Default None Specified
Minimum -1.0 (inclusive)
Maximum 1.0 (inclusive)
Close Window
X

Atmospheric Parameters: HNORM

Description

The atmospheric shell thickness normalized to the planet radius, used to modify angles to get more accurate path lengths near the terminator (Ratio of scale height to the planetary radius). The hnorm parameter is defined as "0.003" for Mars, which is the only planet for which the atmospheric modes are currently used.

Type string
Default None Specified
Internal Default None Specified
Minimum 0.0 (inclusive)
Close Window

Example 1

Create a PVL file of photometric parameters

Description

This example shows the GUI and the parameter name settings. The helper option is used to load the preset parameter values if an existing PVL file is used, and then the required parameter names without any values are manually added.

Command Line

photemplate
Run photemplate to generate a PVL file with the parameter values for the selected photometric models.

GUI Screenshot

photemplate GUI

photemplate GUI

Screenshot of GUI version of the application. The parameter values have been loaded and edited for the output PVL file.

Data File

Links open in a new window.
Output PVL file The output PVL file will contain the photometric parameters to be applied to the input cube. Load the PVL file parameters using the photemplate GUI and manually enter required parameter names without any values assigned.