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I am very new to QGIS for the primary purpose of creating a slopes layer so we know where slopes are above 15% or 20% or whatever we finally decide.
I have used our DEM to create a slope geotif and have used that to try and create a classified layer, but that is where my problems seem to begin. I used this formula to create my classified layer
((slope@1 < 15) OR (slope@1 > 60)) = 0 and while I get a new layer I am not able to view it, no matter how I manipulate the properites. I also tried to follow the instructions for the display that says to do this:
9.4.16. Setting the style for the reclassified layers
- Open the Style tab in the layer’s Properties dialog as usual.
- Under the heading Load min / max values from band, select the Actual (slower) radio button.
- Click the Load button.
The Custom min / max values fields should now populate with 0 and 1, respectively. (If they do not, then there was a mistake with your reclassification of the data, and you will need to go over that part again.)
- Under the heading Contrast enhancement, set the Current dropdown list to Stretch To MinMax.
- Click OK.
I do not come up with the 0 and 1 that the instructions speak of (I am not using their tutorial data) but it seems that I should be able to see the layer.