Hi,

I have a 2d tile game, and I'd like to generate random maps (of size 100x50). I'd like to be able to create small islands, or large continents.

It seems like a standard way to do this is to use perlin noise. You generate a random heightmap, pick a threshold for the water line, and assign tiles their terrain type from that.

Looking at perlin noise implementations, I can't find a description of the domain of the different parameters, or how/if they can be combined to generate small islands vs large continents. Perlin noise seems to have a few parameters:

    persistence
    frequency
    amplitude
    octaves

Is anyone familiar enough with this to describe them, and how they can be combined to create the "clump" size I'm after? I found a posting by a member here that made an interactive demo of perlin noise:

    http://www.java-gaming.org/topics/perlin-landscape-applet/24141/view

but I'm basically just playing with the parameters without really knowing what they're doing. I'm not even sure what the min/max range of each of the above params can be.

I found this article which is pretty much exactly what I want:

    http://www.nolithius.com/game-development/world-generation-breakdown

but the author is using flash which has a perlin noise function built in, so I'm not sure how its version of perlin noise and its parameters map to a .. "standard"? version of perlin noise. The author says:

"Generate a Fractal Grayscale Perlin Noise with an x-frequency of half the width, a y-frequency of half the height, and 8 octaves. For more loose islands, or for larger maps, you can drop the frequency to 1/4th of the width and height or lower, to fit your purposes."

Matching that up with the sample applet from the above user didn't yield expected results.

If anyone is knowledgable about this it'd be awesome to get a clear description memorialized on the nets.

Thank you