[GRASS-dev] [GRASS GIS] #2934: Documentation error in i.vi WRT to MSAVI parameters

[GRASS GIS]

#2934: Documentation error in i.vi WRT to MSAVI parameters
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 Reporter:  pmav99       |      Owner:  grass-dev@…
     Type:  defect       |     Status:  new
 Priority:  normal       |  Milestone:  7.0.4
Component:  Imagery      |    Version:  7.0.3
 Keywords:  i.vi         |        CPU:  Unspecified
 Platform:  Unspecified  |
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 According to `i.vi`'s documentation, the following input parameters are to
 be specified for `MSAVI2` only:

 {{{
 soil_line_slope=float
     Value of the slope of the soil line (MSAVI2 only)
 soil_line_intercept=float
     Value of the intercept of the soil line (MSAVI2 only)
 soil_noise_reduction=float
     Value of the factor of reduction of soil noise (MSAVI2 only)
 }}}

 The formulas for `MSAVI*` are:
 {{{
 MSAVI = s(NIR-s*red-a) / (a*NIR+red-a*s+X*(1+s*s))
 MSAVI2 = (1/2)*(2(NIR+1)-sqrt((2*NIR+1)^2-8(NIR-red)))
 }}}
 AFAIK the formulas are correct, so I guess that the soil parameters should
 be required for `MSAVI` instead of `MSAVI2`. Is that accurate?

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2934>
GRASS GIS <https://grass.osgeo.org>