I made an image by using band math in SNAP, I had some area around of my image that had value of (-3.906) (figure 1), so I used NON (figure2), then they are converted to ‘NaN’ (figure3).
But when I open it in QGIS, at first, it does not have that value in image (figure4) but when I used (properties……singleband pseudocolor….apply…ok) (figure5), then again I have those value in blue color around of my image (figure 6).
My value that I made NAN in SNAP was (-3.906) but its value in here is (-1.163920) that it has some pixels in my image too and I do not know how can I remove it by transparency?
Min/Max in the raster properties do not matter, they are not the actual smallest values. As you selected “cumulative count cut”, these are 2% afar from the smallest and largest values in order to enhance the contrasts.
the only thing I can suggest is to make sure that the actual raster is selected in the table of contents before using the identify tool. Otherwise you will extract the pixel value of any other raster which is currently loaded into the project).
Have you tried entering: From -50 to -1.75 (or something outside the legend) in the transparency range?