Generate a vegetation index

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Index generator

To generate predefined indices based from the imported images.

1. Click the tab Index generator.
2. Select the required Source layer from the menu.
3. A selection of indices is available to generate based on the source layer data type.
4. Check/uncheck the indices required.
5. Click GENERATE.

Available indices

Index Description Formula Image import type
BNDVI - Blue Normalized Difference Vegetation Index NDVI index without red channel availability, for areas sensitive to chlorophyll content. (NIR − BLUE) / (NIR + BLUE) Multispectral (excluding Sequoia)
GNDVI - Green Normalized Difference Vegetation Index NDVI index without red channel availability, for areas sensitive to chlorophyll content. (NIR − GREEN) / (NIR + GREEN) Multispectral
LCI - Leaf Chlorophyll Index

Index to assess chlorophyll content in areas of complete leaf coverage.

Value range clamp between -1 and 1.

(NIR − REDEDGE) / (NIR + RED)  Multispectral
MCARI - Modified Chlorophyll Absorption in Reflective Index Index used to measure chlorophyll concentrations including variations in the Leaf Area Index. 1.2 * (2.5 * (NIR - RED) - 1.3 * (NIR - GREEN)) / maxCoeff(max(RED, max(GREEN, NIR))) Multispectral
NDRE - Normalized Difference Red Edge Index sensitive to chlorophyll content in leaves against soil background effects. This index can only be formulated when the red edge band is available. (NIR − REDEDGE) / (NIR + REDEDGE) Multispectral
NDVI - Normalized Difference Vegetation Index Generic index used for leaf coverage and plant health. (NIR − RED) / (NIR + RED) Multispectral
SIPI2 - Structure Intensive Pigment Index 2

Index used in areas with high variability in canopy structure (e.g. forestry).

Value range clamp between -1 and 1.

(NIR − GREEN) / (NIR − RED) Multispectral
TGI - Triangular Greenness Index RGB index for chlorophyll sensitivity. (GREEN − (0.39 * RED) − (0.61 * BLUE)) / maxCoeff(max(RED, max(GREEN, BLUE))) RGB
VARI - Visible Atmospherically Resistant Index RGB index for leaf coverage. min(1, max(-1, (GREEN − RED) / (GREEN + RED − BLUE) )) RGB, MicaSense
Note 1: min(1, max(-1, ...) is clamping the values between -1 and 1.
Note 2: maxCoeff(max(...max(..)))) is the maximum value on all the bands.  It normalizes the index (see that if bands are defined between 0 and 1, this scale does not change).

 

Index calculator

To generate a custom index using the index calculator.

1. Click the tab Index generator.
2. Select the required Source layer from the menu.
3. Click the button Create custom index.
4. (optional) Name the custom index.
5. Enter the formula using either the Operations buttons or keyboard.
6. When a formula is valid, click PREVIEW.
7. To apply the formula as per the preview, click the button APPLY.
8. Your custom index will appear now as a layer in your layer menu.

Custom indices can be created depending on the available bands from your imported images, these are listed as buttons under Reflectance Map Bands.

The Operations buttons are described below:

Operation Description
( open parenthesis
) close parenthesis
* multiplication
+ addition
- subtraction
/ division
; (semicolon) separator for functions that take more than one parameter 
^ exponentiation
abs absolute value
exp exponential (e^x)
log natural logarithm
max maximum value of a value of a band (or operation),  it returns a scalar value
maxCoeff maximum value of a band (or operation),  it returns a scalar value
mean mean value of a band (or operation), it returns a scalar value
min minimum value between two arguments, separator is ";" (semicolon)
minCoeff minimum value of a band (or operation), it returns a scalar value
sqrt square root

 

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