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 $ISISROOT/appdata/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

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.