A better World Map?

Question

I'm trying to map a 3D world ... at present, I'm looking into the possibility of using
an EnumMap as my Grid reference ....
allowing me to add zones according to the three co-ordinates
then adding the zones to a HashMap which uses the EnumKey as it's Key,
and the zone as the value.
I'm trying to enable lookups by Level, then Row, then Cell ... which would lead to Zone
I have the EnumMap working, but I'm not sure how to create the HashMap from the
EnumMap references
// presume something like this
private static EnumMap<Axis,Integer> map =
   new EnumMap<Axis,Integer>(Axis.class);
public HashMap<Axis,Zone> refAdex =
   new HashMap<Axis,Zone>();
refAdex.put(Axis.Y,new Zone();Axis.Y is the last co-ordinate entry.
Edited by: kcstingel on 29/07/2009 19:42
(shortened the code line width)

Answer 1

While I don't do 3D mapping in Java, I do it in C++ at work quite frequently, and I'll admit, I'm perplexed by your suggestion. I see your logic behind it, but I would like to present an alternative that you may find to be more efficient.
Now, you didn't really say how you plan to display this. If you don't need double precision, consider taking them to floats. If you only need integer precision, consider using ints. I use doubles because memory is cheap, processing is cheap, and doubles are precise, and I optimize if I must.
If you're in for some heavy reading, consider JOGL - it lets you use OpenGL in Java for rendering. Otherwise, you can write some paint methods that do some sorting and iterating of your object vector to determine what to display, where, and when (yes, when is important in 3d graphics!)
If I were doing something in 3D in Java, this is where I would start. Hope this helps!
/** Base class for anything that I will put in my world
public class MyObject {
   private double x_pos, y_pos, z_pos; // could make a 3d point class, unnecessary though
   private String name; // something to reference this object by
   private OtherData data; // other things you want this object to hold/know/contain
   public MyObject(double x, double y, double z, String n, MyModel m){
      x_pos = x;
      y_pos = y;
      z_pos = z;
      name = n;
      model = m;
   // assume accessor methods apply
/** The world where things go
public class MyWorld {
   private Vector<MyObject> population; // the things in my world
   public MyWorld() {
      population = new Vector<MyObject>();
   public void add(MyObject obj) {
      if(obj == null) return; // should throw exception, lazy for example :-)
      // consider bounds checking, like
      // if(obj.x() > MAX_X || obj.x() < MIN_X || ... do for x,y,z, define MIN and MAX somewhere
      //    return; // because it didn't match the bounds
      population.add(obj); // assume if it got here it's okay to add it
public class WorldMain {
   public static void main(String[] args) {
      MyWorld world = new MyWorld();
      MyObject home = new MyObject(0,0,0,"Home Sweet Home");
      MyWorld.add(home);
   } // end main
} I would also consider using a map if we need to, to make it speedier (only if necessary)
// replace this
   private Vector<MyObject> population; // the things in my world
   public MyWorld() {
      population = new Vector<MyObject>();
// with this
   private Map<String, MyObject> population; // the things in my world
   public MyWorld() {
      population = new TreeMap<String, MyObject>();
// and the add method here:
   population.add(obj); // assume if it got here it's okay to add it
// with this
   population.put(obj.name(), obj);