Contents
How do you calculate soil adjusted vegetation index?
Landsat Surface Reflectance-derived SAVI is calculated as a ratio between the R and NIR values with a soil brightness correction factor (L) defined as 0.5 to accommodate most land cover types. In Landsat 4-7, SAVI = ((Band 4 – Band 3) / (Band 4 + Band 3 + 0.5)) * (1.5).
What does NDRE measure?
NDRE is an index that can only be formulated when the Red edge band is available in a sensor. It is sensitive to chlorophyll content in leaves (how green a leaf appears), variability in leaf area, and soil background effects. High values of NDRE represent higher levels of leaf chlorophyll content than lower values.
What is the most commonly used spectral index or ratio?
Vegetation indices
Spectral indices are combinations of spectral reflectance from two or more wavelengths that indicate the relative abundance of features of interest. Vegetation indices are the most popular type, but other indices are available for burned areas, man-made (built-up) features, water, and geologic features.
What are the values of the green vegetation index?
This index minimizes the effects of background soil while emphasizing green vegetation. It uses global coefficients that weigh the pixel values to generate new transformed bands. It is also known as the Landsat TM Tasseled Cap green vegetation index. Values range from -1 to 1.
What should the gamma constant be in ENVI?
The gamma constant is a weighting function that depends on aerosol conditions in the atmosphere. ENVI uses a value of 1.7, which is the recommended value from Gitelson, Kaufman, and Merzylak (1996, page 296). Reference: Gitelson, A., Y. Kaufman, and M. Merzylak. “Use of a Green Channel in Remote Sensing of Global Vegetation from EOS-MODIS.”
When to use non linear vegetation index ( NDVI )?
This non-linear vegetation index is used for global environmental monitoring from satellite imagery and attempts to correct for atmospheric effects. It is similar to NDVI but is less sensitive to atmospheric effects. It is affected by bare soil; therefore, it is not recommended for use in areas of sparse or moderately dense vegetation.
What is the GVI value for Landsat TM?
It uses global coefficients that weigh the pixel values to generate new transformed bands. It is also known as the Landsat TM Tasseled Cap green vegetation index. Values range from -1 to 1. GVI was originally designed for use with Landsat TM, but it will also work with the corresponding bands of Landsat ETM+ and Landsat 8.