@Override
	public double[] get2DData(int px, int pz, int sx, int sz)
	{
		double[] da = a.get2DData(px, pz, sx, sz);
		double[] db;
		
		if(a == b)
			db = da;
		else
			db = b.get2DData(px, pz, sx, sz);
		
        int s = sx*sz;
		for(int i = 0; i < s; i++)
            da[i] = da[i] > db[i] ? da[i] : db[i];
        
        return da;
	}