Obtong, if the landscape is snow - you'd end up with an 18% grey scene using the meter reading from the camera (or a hand-held meter); in this instance you would need to open up by 2 stops to get a "correctly" exposed image. (The same would be true of a very dark scene, but in that instance, you'd need to stop down 2 stops to render it "correct".)

I remember doing a test at college with grey cards - you had to make the same card: 18% grey, white and black; it all had to do with your exposures. Some got the idea quickly, others had problems, but once you worked it out, adjusting to compensate for any scene you were presented with was much easier.