Effective spectral WaveLength  for tmnov image
a most important issue in 4SM



Effective WL for SPOT imageries 
We were lucky that wavelengths to represent SPOT wavebands
appear unquestionably to be 550, 650 and 850 nm

Effective WL for Landsat TM imageries
  • Default procedure: wavelengths are set by default in 4SM, using Godard Space Flight Center data for the TM sensor:
    • @-WLM518.0/610.0/693.0/905.0
    • @-WLm452.0/529.0/624.0/776.0
    • @-cWL000.50/0.53/00.50/00.50 (this info was derived from tmnov seatruth)
    • this results in -WL485.0/571.9/658.5/840.5 by default
  • Explicit your own: if the following arguments are provided in command line, this shall override the default procedure:
    • either your own -WLM..., -WLm... and -cWL... arguments: 4SM computes your own -WL
    • or your own -WL....: they shall be used instead of the default values
  • For this exercise: please, first enable 
    • -WLM518.0/610.0/693.0/905.0
    • -WLm452.0/529.0/624.0/776.0
    • -cWL0.50/0.50/0.50/0.50
  • ==> this will force all WL at mid-waveband
    • @-WL485.0/569.5/658.5/840.5
  • we can allways change that later on



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