MAP_ROUNDING Real
Maximum error which can be tolerated between optimal size ( given by
MAP_FIELD/MAP_CELL) and its rounded value MAP_SIZE (as a power of 2^k
3^p 5^q) when rounding by floor (thus limiting the field of view). If
the rounding error becomes larger, rounding is made by ceiling, which
guarantees a larger field of view, but leads to bigger images.
Default is 0.05.