Have you ever taken the perfect landscape shot only to see later on that its skew? In this quick tutorial, which is based on a post here, I will show a very simple way to correct it without guessing.
I have a simple example using just a simple slightly skew straight line. We will use the Measure Tool for this, you get to this tool by clicking on the Eye Dropper, keep it in then choose from the list of tools.
Using the measure tool draw a line from the one end of the horizon to the other side, this will mark out what you want to be straight.
Once you drew the line select Image->Rotate Canvas->Arbitrary… it will automatically fill in the correct degree.
Once you choose Ok you will get a perfectly straight horizon, all thats left now is to crop the image and be mad at yourself for not holding the camera straight to begin with.
