[Freeciv-Dev] Re: (PR#2749) place_land_type in mapgen

["kayeats@xxxxxxxxxxxxxxxxxxxxxxxxx via RT" <rt@xxxxxxxxxxxxxx>]

> I'm not sure I like your distribution functions yet. In any algortihm
> in which you calculate probabilities in advance, then distribute
> purely according to probabilities, you lose a lot of local effect
> ability. Once you place a forest tile, there needs to be heightened
> probablity of a neighbouring tile being forest. The same for swamps
> and deserts. Mountains/hills are different in that you *do* want to
> break up clumps of these with at least running valleys.

This is a very valid point but I think that if you actually play with it
you'll find it isn't a problem.  To get something that I think the average
joe would find fair I had to weight the algorithms so that clumping was
quite strongly reduced.  This particularly applies to the plains and to
the three layer forests (which admittedly is rather a hack).  Play with
the parameters in those two placing functions (for instance I like 10 in
the forest function, I think such forests make very realistic clumps).
For swamps if you turn them up enough to get a non-negligiable number
you'll see that in some places they clump into large swamps and there are
other scattered swamps too.  I think if you look at wetlands in the world
you will find this quite realistic.

I admit that I lose some flexibility in calculating the distribution in
advance.  However I think it is worth it.  In practice the disadvantages
can be minimized, and the advantages are in having only to loop through
the whole world twice while still guaranteeing up to a random factor
getting the amount of each terrain that you ask for.