شاخص های پوشش گیاهی

انواع شاخص های پوشش گیاهی

انواع شاخص های پوشش گیاهی و نحوه محاسبه آنها

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 CALCULATING RVI: 

                        NIR

                 RVI = -------

                        red

 CALCULATING THE NDVI:

                             NIR-red

                     NDVI = ---------

                             NIR+red

CALCULATING IPVI:

                           NIR

                  IPVI = --------

                         NIR+red

CALCULATING DVI:

                 DVI=NIR-red

CALCULATING PVI:

                  PVI = sin(a)NIR-cos(a)red

a is the angle between the soil line and the NIR axis.

 INDICES TO MINIMIZE SOIL NOISE

 CALCULATING WDVI:

                  WDVI = NIR-g*red 

  g is the slope of the soil line. 

CALCULATING SAVI:

                         NIR-red

                  SAVI = ----------(1+L)

                         NIR+red+L

 where L is a correction factor which ranges from 0 for very high vegetation cover to 1 for very low vegetation cover.  The most typically used value is 0.5 which is for intermediate vegetation 

CALCULATING TSAVI:

                              s(NIR-s*red-a)

                 TSAVI = ---------------------------

                          (a*NIR+red-a*s+X*(1+s*s))

where a is the soil line intercept, s is the soil line slope, and X is an adjustment factor which is set to minimize soil noise (0.08 in original papers).

CALCULATING MSAVI:

                           NIR-red

                 MSAVI = ------------- (1+L)

                          NIR+red+L

 where L = 1 - 2*s*NDVI*WDVI 

and s is the slope of the soil line.

CALCULATING MSAVI2:

             MSAVI2 = (1/2)*(2(NIR+1)-sqrt((2*NIR+1)^2-8(NIR-red)))

 where ^2 signifies the squaring of the value and sqrt() is the square-root operator. 

INDICES TO MINIMIZE ATMOSPHERIC NOISE

CALCULATING GEMI:

                                                       red - 0.125

                GEMI = eta*(1-0.25*eta)- -------------

                                                          1 - red

 where :

                        2*(NIR^2-red^2)+1.5*NIR+0.5*red

                eta = ------------------------------------

                               NIR + red + 0.5

 CALCULATING ARVI:

                            NIR-rb

                ARVI = ----------

                            NIR+rb

 with rb defined as: 

                 rb = red - gamma*(red - blue)

 and gamma usually equal to 1.0

CALCULATING GVI:

     Default version for MSS

           GVI = -0.29*MSS4 - 0.56*MSS5 +0.60*MSS6+0.49*MSS7

     Default version for TM

       GVI = -0.2848*TM1-0.2435*TM2-.5436*TM3+0.7243*TM4+0.0840*TM5-            

              0.1800*TM7

 منبع::gistack.rozblog.com/