/* This file describes the data elements in the */ /* SCATTERING_LAW_FITS_CONTAINER in the GVANF file. */ /* (See the GVANF.LBL and GVANF.FMT label files for details). */ OBJECT = COLUMN NAME = SCATTERING_LAW_ID DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 1 BYTES = 1 VALID_MINIMUM = 0 VALID_MAXIMUM = 4 DESCRIPTION = "Identification number that specifies the analytic scattering law used to fit the observed scattering law. The possible ID numbers and scattering models are 0 Hagfors 1 Exponential 2 Gaussian 3 Rayleigh 4 Muhleman The scattering model determines the interpretation of the remaining fields." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_FLAG_GROUP DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 2 BYTES = 1 DESCRIPTION = "A collection of bit flags describing the results of fitting the observed scattering law to the analytic model. If the corresponding bit is 1, the flag is set. The bit values are 0x01 Fit failed: FIT_PARAMETER_1 too large 0x02 Fit failed: FIT_PARAMETER_1 too small 0x80 Fit failed: unknown error The other bit positions are unused." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_PARAMETER_1 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 3 BYTES = 1 UNIT = "N/A" /* see DESCRIPTION */ DESCRIPTION = "The first parameter solved for in the fit to the observed scattering law. The interpretation of this parameter varies with the scattering model, but for most of them is a measure of the rms roughness of the surface. See the GVDR SIS for a complete description of this field." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_PARAMETER_1_VARIANCE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 4 BYTES = 1 UNIT = "N/A" /* see DESCRIPTION */ DESCRIPTION = "The formal variance of the first fitted parameter, computed using linear propagation of errors through the least squares solution. Since the variance on the observed scattering law estimate is sometimes questionable, this field should be used with caution." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_PARAMETER_2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 5 BYTES = 1 OFFSET = -3 SCALING_FACTOR = 0.012 UNIT = "N/A" /* see DESCRIPTION */ DESCRIPTION = "The second parameter solved for in the fit to the observed scattering law. The interpretation of this parameter varies with the scattering model, but for most of them is a measure of the bulk reflectivity of the surface. See the GVDR SIS for a complete description of this field." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_PARAMETER_2_VARIANCE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 6 BYTES = 1 OFFSET = -9 SCALING_FACTOR = 0.036 UNIT = "N/A" /* see DESCRIPTION */ DESCRIPTION = "The formal variance of the second fitted parameter, computed using linear propagation of errors through the least squares solution. Since the variance on the observed scattering law estimate is sometimes questionable, this field should be used with caution." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_RMS_SLOPE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 7 BYTES = 1 OFFSET = 0 SCALING_FACTOR = 0.08 UNIT = RADIAN VALID_MINIMUM = 0 VALID_MAXIMUM = 20 DESCRIPTION = "The rms surface slope associated with the fit parameters above. This field is computed from analytic expressions for the rms slope implied by a given model, and is quite dependent on that model." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_RMS_SLOPE_VARIANCE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 8 BYTES = 1 OFFSET = -6 SCALING_FACTOR = 0.028 UNIT = "N/A" /* see DESCRIPTION */ DESCRIPTION = "The formal variance of the rms slope given above, computed using linear propagation of errors through the least squares solution and analytic expression for rms slope. Since the variance on the observed scattering law estimate is sometimes questionable, this field should be used with caution. The units of this field are log10(radian-squared). To obtain the actual variance, raise 10 to the value reported here. The result will be in radians-squared." END_OBJECT = COLUMN OBJECT = COLUMN NAME = FIT_RESIDUAL DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 9 BYTES = 1 OFFSET = 0 SCALING_FACTOR = 2 VALID_MINIMUM = 0 VALID_MAXIMUM = 500 DESCRIPTION = "The formal residual of the model's fit to the observed scattering law. It is the sum of squares of the difference between the observed scattering law and the model's prediction, summed over the incidence angles reported in SCATTERING_ANGLE_COUNT. When interpreting the residual, the number of degrees of freedom is two less than the number of angles, because of the two fitted parameters. Since the variance on the observed scattering law estimate is sometimes questionable, this field should be used with caution." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPARE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 10 BYTES = 1 DESCRIPTION = "Unused space to pad the row to an even number of bytes." END_OBJECT = COLUMN