touch screen confusion

Ok I know some touch screen come with a label or datasheet using

XR XL YU YD and others use X- Y- X+ Y+

How do they correspond to each other? is XR == X+?

Im lost here I have found 2 different answers online and find it alarming. So i thought to ask here.

for instance: PAGE 4
https://cache.freescale.com/files/microcontrollers/doc/app_note/AN3632.pdf

All resistive touch screens I have used have top left as low and bottom right as high
So on that basis it corresponds with your thinking..

I suppose you can rotate the touch panel 180 degrees, but as I wave written my own controller I couldn't give a hoot.
If the screen is the wrong way round my software rights it for me...

thanks