Storing pixel based world data

Question

I am making a 2d game with destructable terrain. It will be on iOS but I am looking for ideas or pseudocode, not actual code. I'm wondering how to store a large amount of data. (It will be a large world, approximately 64000 pixels wide and 9600 tall. Each pixel needs a way to store what type of object it is.) I was hoping to use a 2D array but a quick load test showed that this is not feasable (even using a 640x480 grid I dropped below 1 fps) I also tried the method detailed here: http://gmc.yoyogames.com/index.php?showtopic=315851 (I used to use Game Maker and remembered this method) however is seems a bit cumbersome and recombining the objects again is nearly impossible. So what other methods are there? Does anyone know how Worms worked? What about image editors, how do they store the colour of each pixel? Thankyou, YM

Answer 1

I am most likely going to use Polygon based storage.

Answer 2

Run-length encoding can help with your memory issues