I am working with different VIs which can calculate the concentration of chlorophyll and I know the value range for NDVI for example is -1 to +1.
Is it same with all VIs or depends on different VIS?
Thanks in advance.
as nearly every vegetation index was developed / published by different researchers they have completely different value ranges. Many of them create data between 0 and 1 but this is no consistent standard.
Please also note that, strictly speaking, NDVI doesn't measure chlorophyll concentration but is a measure for general vitality and any value below 0 indicates water.
Article A review of vegetation indices
Conference Paper A review of multispectral vegetation indices for biomass estimation
Dear Mohamad,
Vegetation indices constitute a generally poor and rather obsolete approach to the analysis of satellite remote sensing data. However, if you really want to use them, you can find out for yourself their range of variability by inserting extreme values of the various channels into the formulas.
NDVI = (NIR - RED) / (NIR + RED)
where RED and NIR are the (positive) red and near-infrared reflectance, which themselves typically vary within the range [0.0, 1.0]. So,
* if RED = 0.0, NDVI = 1.0
* if NIR = 0.0, NDVI = -1.0
* if RED = NIR, NDVI = 0.0
Hence, NDVI cannot exceed [-1.0, 1.0] by definition, as you noted in your question.
Similarly, the Simple Ratio
SR = NIR/RED
can take on values in the range [0.0, infinity]:
* if RED -> 0, SR -> infinity
* if NIR -> 0, SR -> 0.0
If you plan to use another vegetation index, plug the minimum and maximum values of the input data in the formula and determine the range of the index.
Cheers, Michel.
Further to the theory explained by Michel so well, in practice, NDVI calculated from RED and NIR spectral bands measured from ASTER/LANDSAT satellites or at the ground seems not have been lower than -0.3 (both attachments). I would be interested to be referred to lower measured values.
Various regression techniques applied to available spectral band measurements have produced long ago (1985 attached) and recently (e.g. my mangrove papers) the better proxies of green biomass and other land cover features.
Article Fine resolution distribution modelling of endemics in Majell...
Article Ground-based reflectance measurements for standing crop estimates.
Thank you so very much for your help and your answers
@Andreas
@Hein Van Gils
@Michel M. Verstraete
there are many VI (vegetation indices) available for analyzing vegetation in an image.
NDVI (normalized difference vegetation index ) is used to detect the greenness in the image. It can be used to relate chlorophyll content.
if the value approaches 1 , it is an indicator of healthy vegetation(green content).
0.1 or less= area of barren rock,sand, snow
0.2 to 0.5 = shrubs , grassland and senescence crops
0.6 to 0.9=dense vegetation
there are different ranges for different VI ,and there are many to choose from.
following are few , with there ranges .
Hello,
Is it possible to have the range values of others vegetations index as the last colomn of the table presented below by Tarun Khatana ?
I calculate those of GNDVI, RDVI, SAVI, VIGreen, with Landsat OLI and I would like to check if they are in the good range.
Thanks!
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