Vegetation indices are an important tool for the remote sensing researcher involved with vegetation studies in the field. Since different surfaces reflect light differently, measurements of this reflectance and absorption can provide data on the targets. Vegetation that is photosynthetically active absorbs more red light and reflects most of the near infrared light that shines on it. A vegetation index, like the Normalized Difference Vegetation Index (NDVI) works as an indicator that describes the greenness or density and health of vegetation based on measurement of absorption and reflectance.

NDVI is calculated as the difference between the red and near infrared bands of a spectral measurement according to the forumula: NDVI = (NIR-RED)/(NIR+RED). The bigger the difference/higher the measurement, the healthier/greener the vegetation.

All SPECTRAL EVOLUTION spectroradiometers and spectrometers are equipped with DARWin SP Data Acquisition software. From the DARWin menu there are 19 vegetation indices including NDVI immediately available from a pull down menu. These indices include:

• GRVI (Green Ratio Vegetation Index)
• SR (Simple Ratio Vegetation Index)
• DVI (Difference Vegetation Index)
• SAVI (Soil Adjusted Vegetation Index)
• Red/Green (Red Green Ratio)
• ARVI (Atmospherically Resistant Vegetation Index)
• Green NDVI (Green Normalized Difference Vegetation Index)
• EVI (Enhanced Vegetation Index)
• MSAVI2 (Modified Soil Adjusted Vegetation Index Type II)
• IPVI (Infrared Percentage Vegetation Index)
• Sum Green (Summed Green Vegetation Index)
• PRI (Photochemical Reflectance Index)
• NDVI 705 (Red Edge Normalized Vegetation Index)
• WBI (Water Band Index)
• NDWI (Normalized Difference Water Index)
• PAR (Photosynthetically Active Radiation)

Using the indices with our agricultural spectroradiometers and spectrometers allows you to bring your research and analysis to the field with reliable, high resolution, and accurate results. Applications can include:

• Vegetation dynamics
• Plant phenological changes over time
• Biomass production
• Non-destructive measurement of canopy greening, senescence, and stress
• Soil moisture
• Pasture condition and performance
• Changes in range land
• Estimating crop yields
• Land cover classification
• Influx or sequestration
• Plant photosynthesis activity
• Leaf area index (LAI) measurement

The PSR+ is a field portable spectroradiometer for remote sensing applications including vegetation studies. With DARWin SP Data Acquisition Software included, it provides instant access to 19 vegetation indices for your research.

From the DARWin SP screen, the 19 vegetation indices including NDVI are accessed via a pull down menu.