Hey guys,
i´m trying to create an NDVI map from Landsat 8 OLI images by using raster calculator witth the NDVI formula (NIR-Red / NIR+Red).
So far it worked out pretty good, but I have a few clouds in my satelllite data which I´m trying to mask out.
I already used the QA band for cloud and cloud shadow masking, but I don´t know how to apply it on my calculations.
I tried to put the cloud values to zero, but then I get NDVI values which ranges from -110 to 32. So I think this way doesn´t work properly.
I would be grateful on suggestions on how to handle cloud cover in NDVI calculations.
Thank you in advance!
mask the clouds with 'nodata' and not 0 since 0 is a valid number. nodata cells will not be included in calculations
Hello Dan,
sorry, that is actually what I did. Cloud cover values have "nodata" in my raster.
I dont really understand why I get these results because the values in NIR band range from -0.1 to 0.8 and in the RED band from -0.1 to 0.7. Clouds have no data and anyways the NDVI ranges from -110 to 32.
When you say 'mask' those areas should not be used in the calculation at all. It sounds like you aren't setting a mask in your Environments setting and/or you haven't assigned nodata to the areas covered with cloud... which should propagate through all the bands., so check each band.