The general approach is called hysteresis: instead of immediately changing when you cross a border, you change only after you are some distance past the border.
For the simplest example, suppose you want to draw a warning on the screen if you are too close to something. The straightforward code is:
if distance < 20:
But if you're wobbling between 20.001 and 19.999, the warning might flash on and off. Instead, you can
- remember whether the warning is on or off
- use a different threshold for turning it on and turning it off
The code is a bit longer (which is probably why people don't do it all the time):
if warning_displayed and distance > 22:
warning_displayed = false
else if not warning_displayed and distance < 18:
warning_displayed = true
Now what happens? If you're wobbling between 20.001 and 19.999 the warning will either stay on (if you last went below 18) or it will stay off (if you last went above 22), but it won't flash on and off.
The same general idea can be used for loading map areas in Skyrim. The wikipedia article gives lots of examples of where this technique comes in handy (not just maps or games or software).