Question

I am developing a game for the web. The map of this game will be a minimum of 2000km by 2000km. I want to be able to encode elevation and terrain type at some level of granularity – 100m X 100m for example.

For a 2000km by 2000km map storing this information in 100m² buckets would mean 20000 by 20000 elements or a total of 400,000,000 records in a database.

Is there some other way of storing this type of information?

MORE INFORMATION

The map itself will not ever be displayed in its entirety. Units will be moved on the map in a turn based fashion and the players will get feedback on where they are located and what the local area looks like. Terrain will dictate speed and prohibition of movement.

I guess I am trying to say that the map will be used for the game and not necessarily for a graphical or display purposes.

Answer 1

I would treat it differently, by separating terrain type and elevation.

1. Terrain type, I assume, does not change as rapidly as elevation – there are probably sectors of the same type of terrain that stretch over much longer than the lowest level of granularity. I would map those sectors into database records or some kind of hash table, depending on performance, memory and other requirements.

2. Elevation I would assume is semi-contiuous, as it changes gradually for the most part. I would try to map the values into set of continuous functions (different sets between parts that are not continues, as in sudden change in elevation). For any set of coordinates for which the terrain is the same elevation or can be described by a simple function, you just need to define the range this function covers. This should reduce much the amount of information you need to record to describe the elevation at each point in the terrain.

So basically I would break down the map into different sectors which compose of (x,y) ranges, once for terrain type and once for terrain elevation, and build a hash table for each which can return the appropriate value as needed.