© PSI (Photon Systems Instruments), spol. s r. o.
36
Two possibilities exist to define a custom index:
1.
Offline calculation of the desired index from raw spectral data in Excel (independently on SpectraPen
software).
2.
Adding the custom formula to the list of pre-defined parameters in the PolyPen software.
a.
Write a custom formula in the file Formulas.txt located in folder Config (Fig. 32) in the main
PolyPen program folder.
b.
Please follow the parameter syntax. For example - the definition of SAVI index:
Transmitance:SAVI:Soil-Adjusted Vegetation Index:(1+0.5)*(Transmitance[780nm]-
Transmitance[670nm])/(Transmitance[780nm]+Transmitance[670nm]+0.5)
Each index description part is separated with colon.
The first part is a data set source data (e.g.
Transmittance
).
The second part is a name/title of the index (e.g.
SAVI
).
The third part is a detailed description (e.g.
Soil-Adjusted Vegetation Index
).
The last part is a formula of the defined parameter (e.g.
(1+0.5)*(Transmitance[780nm]...)
.
c.
Restart the SpectraPen software after editing of the Formulas.txt file.
d.
New index appears in the list and also in the exported data (Fig. 33).
Fig. 32
Formulas configuration file – adding new index
11
HOW CAN I PROGRAM MY OWN INDEX IN THE POLYPEN RP 400
