Method getMapData

src/main/java/net/minecraft/item/ItemMap.java:45–63

(ItemStack stack, World worldIn)

    }

    public MapData getMapData(ItemStack stack, World worldIn)
    {
        String s = "map_" + stack.getMetadata();
        MapData mapdata = (MapData)worldIn.loadItemData(MapData.class, s);

        if (mapdata == null && !worldIn.isRemote)
        {
            stack.setItemDamage(worldIn.getUniqueDataId("map"));
            s = "map_" + stack.getMetadata();
            mapdata = new MapData(s);
            mapdata.scale = 3;
            mapdata.calculateMapCenter(worldIn.getWorldInfo().getSpawnX(), worldIn.getWorldInfo().getSpawnZ(), mapdata.scale);
            mapdata.dimension = (byte)worldIn.provider.getDimensionId();
            mapdata.markDirty();
            worldIn.setItemData(s, mapdata);
        }

        return mapdata;
    }

    public void updateMapData(World worldIn, Entity viewer, MapData data)
    {