If you change this value by hand, you should call Normalize
afterwards. However, note the following:
The Normalize method sets the bottom left-hand point to be the point that lies furthest west. Similarly, Normalize sets the top right-hand point as the point that lies furthest east.
If the bounding box is intersected by the prime meridian (the zero line of longitude through Greenwich) then there are two possibilities for the bounding box. The first is a comparatively small box, with two corners each lying either side of the meridian. The second possibility is a large rectangle that wraps around the earth, but does not cross the meridian. The solution to this ambiguity is to check if the meridian is visible on the user's map and carefully select the corners from which the desired bounding box is constructed. This is the developer's responsibility. It should be noted that this consideration is only of real concern when mapping in Western Europe, North Africa and the poles.