You're thinking of the Random Number Seed.
If the Random Number Seed is untouched, and no major changes are done to the core (usually, the script and settings of the map), the map will be exactly the same, and you should, in theory, be placed in the same position every time.
If you pre-define your seed (Rather than leaving it random), then the result will be 100% the same every time assuming the settings and database remain unchanged (though even with database, I presume that it will remain unchanged).
Got Lakes from what I remember, has A LOT of settings, including for randomized inner settings (like Age, Wettness etc in regular maps), if those are left to a random, then yes, they will be random, but if they are pre-defined, then you will generally get a similiar looking map, but with the actual map generation still left to a random map generator. When you press Restart, and haven't defined the seed yourself, the seed is changed every time you restart. Hence different maps.