X and Y Global headers for tables (Maps)

[rnd-ash]

I am using EGUI for an ECU tuning tool I am writing, and found that there is one missing feature to tables:

Whilst this table can be understood, it is not clear as to what the X and Y headers are trying to indicate.

Therefore I would like to achieve something like this:

This would make the user more easily understand what the X and Y columns are indicating.