How to calculate MSAVI using QGIS
- 1. Modified Soil-Adjusted Vegetation Index
- 2. Credits : https://www.sciencedirect.com/science/article/pii/S1110982317300327 EMR -Vs- Land features The spectral responses of electro magnetic radiation (EMR) varies with spatial objects as shown here
- 3. Credits : https://earthobservatory.nasa.gov/Features/MeasuringVegetation/measuring_vegetation_2.php If there is much more reflected light in Near-infrared wavelengths than in visible wavelengths, then the vegetation in that pixel is likely to be dense - EarthObservatory, NASA Electro Magnetic Radiation – Vs- Vegetation
- 4. Credits : https://landsat.usgs.gov/atmospheric-transmittance-information http://gsp.humboldt.edu/OLM/Courses/GSP_216_Online/lesson2-1/vegetation.html Bands correspond to Vegetation
- 5. Bands Wavelength (micrometers) Resolution (meters) B1 - Ultra Blue 0.435 - 0.451 30 B2 - Blue 0.452 - 0.512 30 B3 - Green 0.533 - 0.590 30 B4 - Red 0.636 - 0.673 30 B5 - NIR 0.851 - 0.879 30 B6 – SWIR 1 1.566 - 1.651 30 B7 - SWIR 2 2.107 - 2.294 30 B8 - Pan 0.503 - 0.676 15 B9 - Cirrus 1.363 - 1.384 30 B10 - TIRS 1 10.60 - 11.19 100 * (30) B11 - TIRS 2 11.50 - 12.51 100 * (30) Band Specifications of Landsat - 8 Vegetation can be monitored using Red and NIR bands of Landsat
- 6. Vegetation - MSAVI MSAVI Credits : https://en.wikipedia.org/wiki/Normalized_difference_vegetation_index Red InfraRed Modified Soil-Adjusted Vegetation Index MSAVI result
- 7. Go to main menu >> Choose Raster >> Raster Calculator Output Formula Input Computing MSAVI using QGIS MSAVI Formula : ( (2x NIR +1) - sqrt( (2x NIR +1)2 - 8x (NIR – Red)) ) / 2
- 8. Range of MSAVI : -1 to +1 Higher value (towards 1) - Density of vegetation Lower value (towards -1) - Lack of vegetation (water, bare soil, built-up area, etc) MSAVI : (2x NIR +1) - sqrt((2x NIR +1) -8x (NIR – Red)) 2 Ref: Raster styling in QGIS Representation of MSAVI using QGIS 2
- 9. NDVI and MSAVI NDVI is an estimate of the above ground biomass. NDVI interprets the organic matter to the soil when it is not being harvested. MSAVI is an estimate of organic matter with site specific soil-factors. MSAVI enhances the vegetation when the conditions are arid or semi arid MSAVI reduces the influence of soil color (significantly the spectral signal ); thus it holds good in estimating biomass above ground soil. Application of NDVI and MSAVI Paddy Field Grassland
- 10. Comparison of NDVI and MSAVI NDVI MSAVI
- 11. Resampling Load Raster layer to be resampled to QGIS Processing Toolbox >> Search for Resampling Algorithm (eg:) >> Resampling with BSpline Algorithm r.resamp.bspline - Performs bilinear or bicubic spline interpolation with Tykhonov regularization. Image Enhancement techniques Edge Enhancing Load Raster layer to be resampled to QGIS Processing Toolbox >> Search for Filtering Algorithms (eg:) >> Choose Remove Small Pixels with BSpline Algorithm Many Filtering Algorithms - Performed with bilinear or bicubic interpolations to remove chunks. Try with many other image enhancement algorithms.........
- 12. Try with other filtering algorithms... Before enhancement Image Enhancement techniques Here is an output of enhanced image using resampling and edge-enhancement After enhancement