Spectral Indices¶
Spectral indices output a single value between -1 and 1 for each pixel. Unless you want to display a grayscale image, you probably want to apply a colormap after computing the index.
normalizedDifference
¶
Computes the normalized difference of two bands:
normalized_difference = (x - y) / (x + y)
normalized_difference
always uses the first two bands in the pre-assembled
image as x
and y
respectively.
To create the Normalized difference vegetation index (NDVI), for
example, you would pass the near-infrared band and the red band as the first two
images to the imageBands
prop in the combineBands
module.
enhancedVegetationIndex
¶
Computes the Enhanced Vegetation Index (EVI).
Layers are expected to exist as near-infrared, red, and blue bands on the
input image, respectively. For example, with Landsat 8 data, you would pass
bands 5, 4, and 2 to the imageBands
prop in the combineBands
module in that order.
soilAdjustedVegetationIndex
¶
Computes the Soil Adjusted Vegetation Index (SAVI).
Layers are expected to exist as near-infrared and red bands on the input
image, respectively. For example, with Landsat 8 data, you would pass bands 5
and 4 to the imageBands
prop in the combineBands
module in
that order.
modifiedSoilAdjustedVegetationIndex
¶
Computes the Modified Soil Adjusted Vegetation Index (MSAVI).
Layers are expected to exist as near-infrared and red bands on the input
image, respectively. For example, with Landsat 8 data, you would pass bands 5
and 4 to the imageBands
prop in the combineBands
module in
that order.