How to use

markDirty

method

in

net.minecraft.world.storage.MapData

public static ItemStack setupNewMap(World worldIn, double worldX, double worldZ, byte scale, boolean trackingPosition, boolean unlimitedTracking)
{
  ItemStack itemstack = new ItemStack(ModItems.EREBUS_MAP_FILLED, 1, worldIn.getUniqueDataId("map"));
  String s = "map_" + itemstack.getMetadata();
  MapData mapdata = new MapData(s);
  worldIn.setData(s, mapdata);
  mapdata.scale = scale;
  mapdata.calculateMapCenter(worldX, worldZ, mapdata.scale);
  mapdata.dimension = worldIn.provider.getDimension();
  mapdata.trackingPosition = trackingPosition;
  mapdata.unlimitedTracking = unlimitedTracking;
  mapdata.markDirty();
  return itemstack;
}

protected static void enableMapTracking(ItemStack p_185064_0_, World p_185064_1_)
{
  MapData mapdata = ((ItemErebusMap) ModItems.EREBUS_MAP_FILLED).getMapData(p_185064_0_, p_185064_1_);
  p_185064_0_.setItemDamage(p_185064_1_.getUniqueDataId("map"));
  MapData mapdata1 = new MapData("map_" + p_185064_0_.getMetadata());
  mapdata1.trackingPosition = true;
  if (mapdata != null)
  {
    mapdata1.xCenter = mapdata.xCenter;
    mapdata1.zCenter = mapdata.zCenter;
    mapdata1.scale = mapdata.scale;
    mapdata1.dimension = mapdata.dimension;
    mapdata1.markDirty();
    p_185064_1_.setData("map_" + p_185064_0_.getMetadata(), mapdata1);
  }
}

mapdata.addTargetDecoration(itemstack, treasurePos, "x", Type.TARGET_X);
mapdata.markDirty();

protected static void scaleMap(ItemStack p_185063_0_, World p_185063_1_, int p_185063_2_)
{
  MapData mapdata = ((ItemErebusMap) ModItems.EREBUS_MAP_FILLED).getMapData(p_185063_0_, p_185063_1_);
  p_185063_0_.setItemDamage(p_185063_1_.getUniqueDataId("map"));
  MapData mapdata1 = new MapData("map_" + p_185063_0_.getMetadata());
  if (mapdata != null)
  {
    mapdata1.scale = (byte)MathHelper.clamp(mapdata.scale + p_185063_2_, 0, 4);
    mapdata1.trackingPosition = mapdata.trackingPosition;
    mapdata1.calculateMapCenter((double)mapdata.xCenter, (double)mapdata.zCenter, mapdata1.scale);
    mapdata1.dimension = mapdata.dimension;
    mapdata1.markDirty();
    p_185063_1_.setData("map_" + p_185063_0_.getMetadata(), mapdata1);
  }
}

@Nullable
public MapData getMapData(ItemStack stack, World worldIn)
{
  String s = "map_" + stack.getMetadata();
  MapData mapdata = (MapData)worldIn.loadData(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((double)worldIn.getWorldInfo().getSpawnX(), (double)worldIn.getWorldInfo().getSpawnZ(), mapdata.scale);
    mapdata.dimension = worldIn.provider.getDimension();
    mapdata.markDirty();
    worldIn.setData(s, mapdata);
  }
  return mapdata;
}