Basically just rephrasing what Dr Super Good said;
(Oh and this is after A LOT of research)
ALL maps can be unprotected, no matter WHAT you do to it.
Basically, as long as your game can run the map, then it can be opened with mpq editors and changed/cheated/hacked.
The things you CAN do are pretty simple;
A great solution just like Dr SG said was
WC3 Map optimizer by Vex, it's the perfect solution for anti-noob hacking, it even obsuficates your code for you.
However, if you want to go deeper, you need to know JASS, and there are multiple ways of coding in ways to make it really hard to open/read for the hacker, eg: instead of using a -gold string, you do something like "-" + "g" + "o" + "l" + "d", which when looked at by the hacker, makes it harder to read, but that's not map protection, it just makes it a little harder.
Anyway, if whoever wants, PM me, and I'll send you a great site that I learned A LOT from, so feel free.