What is the NDVI equation?

Posted on by Dominique Stacey

What is the NDVI equation?

NDVI is calculated as a ratio between the red (R) and near infrared (NIR) values in traditional fashion: (NIR – R) / (NIR + R) In Landsat 4-7, NDVI = (Band 4 – Band 3) / (Band 4 + Band 3).

How is NDVI calculated in Modis?

In MODIS, Red and NIR are represented by band 1 and 2. This is the underlying concept of calculating NDVI….NDVI = (NIR — Red) / (NIR + Red)

  1. Import the image collection of NDVI from MODIS data catalog.
  2. Filter the date and the area of interest.
  3. Colorized or visualize the NDVI image.
  4. Display the NDVI.

What is NDVI and how is it calculated?

NDVI is calculated from the visible and near-infrared light reflected by vegetation. Healthy vegetation (left) absorbs most of the visible light that hits it, and reflects a large portion of the near-infrared light. Unhealthy or sparse vegetation (right) reflects more visible light and less near-infrared light.

What is the formula for calculating NDVI from multispectral imagery?

NDVI = (NIR-R) ./ (NIR + R); % [In this step I couldn’t use / to compute, could you tell me why?]

How does Google Earth calculate NDVI engine?

Calculate NDVI from Recent Sentinel Satellite Imagery in Google Earth Engine

  1. Summary.
  2. Get started in Earth Engine (new users)
  3. Import Sentinel-2 Imagery within your study area.
  4. Calculate NDVI from the Sentinel-2 imagery.
  5. Select the Most Recent Image.
  6. Add the Most Recent NDVI Image to the Map.
  7. You’re done!
  8. More Resources.

How do I get NDVI?

To calculate NDVI in QGIS, use the raster calculator to subtract values of the Red band from the Near-infrared (NIR) band, then divide by the sum of the Red and NIR bands. All you need is reflectance values in the Red and NIR bands from any kind of imagery and an installation of QGIS.

How do you calculate Savi?

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).

How is NDVI value calculated?

What is NDVI good for?

Simply put, NDVI helps to differentiate vegetation from other types of land cover (artificial) and determine its overall state. It also allows to define and visualize vegetated areas on the map as well as detect abnormal changes in the growth process.