Hi

I am doing an NDVI on a worldview2 image contains 4 bands(R,G,B, NIR). I have faces some problems that I would be pleased if anyone can guide me .I am using ENVI by the way.

1-the background area that had the (no value) gained 0 value in NDVI image. Since 0 is considered a value in this index what is your solution. I made a mask layer of background area and used it for spatial Subset but there is no difference and areas are recognized as 0 value.

2- for defining the NDVI bands I defined red:3 and IR:4 is that correct.

3- is it recommended to exclude water bodies from the analysis. Since my license does not have access to feature extraction what is your suggestion for this

thank