RNSF(5) File Formats Manual RNSF(5)

rnsf — Rad-Net Scattering Functions file format

rnsf is a text file format that describes a phase function whose type and parameters can vary spectrally. Its data are described for a set of wavelengths or spectral bands that must be listed in ascending order.

Characters behind the hash mark (#) are considered comments and are therefore ignored, as well as empty lines, i.e. lines without any characters or composed only of spaces and tabs.

The file format is as follows:

⟨rnsf⟩ ::= ⟨per-wlen-phase-func⟩ | ⟨per-band-phase-func⟩
 
⟨per-wlen-phase-func⟩ ::= ⟨wavelengths-count⟩
⟨wlen-phase-func⟩
...
⟨wlen-phase-func⟩ ::= ⟨wavelength⟩ ⟨phase-func⟩
⟨wavelengths-count⟩ ::= integer
⟨wavelength⟩ ::= real # In nanometers
 
⟨per-band-phase-func⟩ ::= ⟨bands-count⟩
⟨band-phase-func⟩
...
⟨band-phase-func⟩ ::= ⟨length-min⟩ ⟨length-max⟩ ⟨phase-func⟩
⟨bands-count⟩ ::= integer
⟨length-min⟩ ::= real # Inclusive bound in nanometers
⟨length-max⟩ ::= real # Inclusive bound in nanometers
 
⟨phase-func⟩ ::= ⟨phase-func-HG⟩ | ⟨phase-func-discrete⟩
 
⟨phase-func-HG⟩ ::= ⟨asymmetric-param⟩
⟨asymmetric-param⟩ ::= real # In [-1, 1]
 
⟨phase-func-discrete⟩ ::= ⟨angles-count⟩
⟨value⟩
[⟨pair⟩ ...] # Ascending angles
⟨value⟩
⟨angles-count⟩ ::= integer # Must be >= 2
⟨pair⟩ ::= ⟨theta⟩ ⟨value⟩
⟨theta⟩ ::= real # In radians
⟨value⟩ ::= real # Not necessarily normalized

Spectrally varying phase function on two spectral bands: a band for the visible part of the spectrum for which a Henyey & Greenstein phase function is used, and a band for long waves with a discretized phase function on 4 angles:

bands 2

# Visible part
380 780 HG 0

# Inrared
1000 100000 discrete 4
  0       0.079577
  0.78    0.079577
  2.35    0.079577
  3.14159 0.079577

Phase function for a set of 10 wavelengths. Use a discrete phase function for short waves and Henyey & Greenstein for long waves:

wavelengths 10

# Short waves
430 discrete 8
  0           0.02
  0.23        0.04
  0.5         0.07
  0.7         0.15
  1.54        1.23
  1.8         0.02
  2           1.23
  3.14159     0.79
450 discrete 2
  0           0.5
  3.14159     0.796
750 discrete 4
  0           0.079577
  0.78        0.079577
  2.35        0.079577
  3.14159     0.079577

# Long waves
1100    HG   -0.1
1300    HG    0.57
1400    HG    0.4
2100    HG    0.3
2500    HG   -0.9
2900    HG   -0.4
100000  HG    0.0

The rnsf format was first developed for the htrdr-planeto(1) program.

September 15, 2023 UNIX