title: Random 2D Tile-Map Generating Algorithm
body: <p>Can anyone tell me a way to generate island structures or hill structures like in minecraft?</p>
  
  <p>I'm just searching for a proper THEORY for that random-shape generating, but it should keep a defined base pattern..</p>
  
  <p>like: islands schould be rounded but variate in shape and scale ( min/max width &amp; height ).</p>
  
  <p>or: rivers schould not be straight lines, they should have curves and a random width.</p>
  
  <p>or even: generating some sort of forest, where trees are placed in a way that the user can still walk through the forest (that's a simple one I think, just say that some blocks around a tree should remain blank, if code tries to put more trees around the last one )</p>
  
  <p>What kind of math can I use to do such things?</p>
  
  <p>I would be glad for some links for tutorials or references. I've searches all around the web for hours, but all I could find was some books to buy like "game mathematics" or something, but my budget is set to zero.</p>
  
  <p>EDIT:</p>
  
  <p>First of all, I'm sorry for my bad englisch.</p>
  
  <p>Secondary I want to thank all of you for your answers. These are great references and I'll spend much time to go deeper in that.</p>