Remapping is a more modern term for chip tuning.
Remapping is to modify the software within the engines ECU (Engines brain!) to improve its efficency to get out of it, what its capable of.
but in this case, remapping is for more the latest vehicles. where a vehicle has re-programable memory.
meaning that the computer can be re-flashed (programmed) over & over.
leaving us with the means to be able to program memory without much dissasembly of the vehicle, & easily write revisions.
Chip tuning being the other term, reffers to the earlier vehicles that use one time programable memory (OTP) which meant
that the ECU had to be removed to remove the computer chip holding the relevant data, read the data.
modify the data, before writing your new modifications to a replacement chip.
revise the software? means either using ultra-violet light to erase & re-write. Or throw i the bin and start over.
Many modern ECUs still require removals for programming, but on a the different end of the spectrum to chip tuning.
These days, the reason for this is because manufacture is putting so much security in place to try prevent access.
Even though they still use re-programable memory, bootmode (Like a PC BIOS) is required to get to all data, to bypass security thats in place.