I have a large raster image depicting land use. It's a singleband pseudocolor image whose values are contained in a text file. There are 5 classes.
Following the example of this question I thought I could just use the Raster Calculator tool like this (where 1 is the desired class):
filename@1 = 1
Unfortunately, whenever I do this, QGIS just returns a raster with only missing values. Any idea what I'm doing wrong?
EDIT:
Here is what my color ramp looks like, as well as the raster once the colors are applied:
Let's say I want to extract all the dark blue pixels containing water values. These have a value of 4, but they are within Band 1. I wonder if this is where I'm having trouble.
Here's the Raster Calculator operation I'm performing.
But instead of receiving a raster with the dark blue areas, all I get is a raster covering the entire area with missing values.