I have a raster with some no-data cells.
I want to visualise raster values using a colour map and set the no data values to transparent. I am attempting to do this using the transparency tab in the layer properties dialogue.
This all went well when I am viewing a small section of the raster:
However, when I zoom out the no data pixels become visible and the identify tool says the value is now -inf.
There seems to be a trigger point at which this happens, for all larger scales the no data values are left transparent and for all smaller scales I get this strange -inf thing.
Why does this happen and how can I stop it?
This is only the 3rd time I have used QGIS so apologies if this is a well known thing that is easily solvable - I couldn't seem to find a similar question.
Due to workplace limitations I am forced to use QGIS 2.2.0-Valmiera.
The raster is a .tif