I'm trying to run the indices Savi and EVI at landsat 7 & 8. About SAVI I read this from ESRI and explains very good this index. About SAVI I have a question, I will choose buy my self the L factor if it is 1, 0.5 or 0? About EVI index I will use the some value for L factor like SAVI? and what about coefitiens C1 & C2.
For the SAVI, your choice will depend on the percentage of vegetation cover.
If you don't see the soil, there no need to correct for the soil. Therefore you should use 0, which is equivalent to the use of NDVI.
If you have a very sparse vegetation, you mainly see the soil. Thefore you could use 1.
The most commonly used value is 0.5 , the "safest" guess when you don't know what to choose.
For EVI, C1 = 6, C2 = 7.5 , L = 1 and G = 2.5 have been used for MODIS and for Landsat.
Of course, the above mentioned values are valid if you work with reflectance values of Landsat, not based on the DN.
I am not sure if calculations of EVI and SAVI changed, but I do not see the G multiplying factor anymore. According to the last Product Guide from Landsat, the EVI and SAVI are calculated as follows:
EVI = (Band 5 – Band 4) / (Band 5 + 6 * Band 4 – 7.5 * Band 2 + 1) SAVI = ((Band 5 – Band 4) / (Band 5 + Band 4 + 0.5))* (1.5)
You can find the report here: http://landsat.usgs.gov/documents/si_product_guide.pdf
For Landstat 4&5, it is
[(band 4 - band 3) / (band 3 + band 4 + 0.5)] × 1.5
For Landstat 8, it is
(band 5 - band 4) / (band 5 + band 4 + 0.5)] × 1.5