How to update tiles

With Distributed Tiling service, SuperMap iServer can generate tiles either with multiple scales or within a specified boundary. Those tiles can be used in server-side or directly in client side as it is offline status. In general, you should think about the updating issue of the tiles when the maps on the server changed, e.g., the style of a layer changed or some elements in a layer are added, deleted or modified. In this case, to update the tiles could keep the data in time.

You don't need to worry about the tiles whether they are the latest or out of date when there are some changes on the maps. SuperMap iServer will automatically check each tiles. If a tile checked is out of date, a new tile will replace the old one dynamically. Besides the automatic update, you can also set the tiles as read-only, and manually update tiles by Distributed Map Tiling service.

Due to the massive quantity of data, the efficiency of the Distributed Map Tiling service is better than the automatic tile updating. So, SuperMap recommends you update tiles manually or use the tiling tool to update tiles.

• Update and append tiles manually
• Tile updating tool
  • Methods
  • Directional update
  • Note
• Remove tiles with specified bounds

Update and append tiles manually

The Distributed Map Tiling service of SuperMap iServer supports updating and appending new tiles into the existing tiles. For instance, to update or append new tiles with certain scales or certain bounds into the existing tiles. SuperMap supports the following formats of tiles to be updated or appended: FastDFS, MongoDB, SMTiles, MBTiles, UGCV5, SVTiles (vector based), UTFGrid (attribute based).

The steps of the "update and append tiles manually" are identical with How to use Distributed Map Tiling service. You need to select a path to place the tiles (such as output path\sqlite\) or to the tile library (determined by storage ID). Meanwhile, you should specify the scale and the bound that you want to append. If a new tile is identical with the existing tile, the old one will be replaced.

As for the distributed tiles, there will be prompted with "The tiles exist. Do you want to create a new tiling version？“ before starting to tile. In this case, you should select No, and select an exist version for updating or appending. Then, click OK.

Tile updating tool

SuperMap iServer provides a tile updating tool for importing the tiles of FastDFS, MongoDB, SMTiles, and UGCV5.

Through this tool, you could:

• Update tiles by other tiles
• Combine tiles which are stored in a distributed way
• According to the specified scale and the bound, export the distributing tiles into the file format (such as SMTiles) for conveniently distributing.

Methods

Log in iServer WebManager, click Services>Advanced>Tiles Update. The detailed steps are:

1. Click Create tile update task;
2. Set Input tile set: the source of the tiles
3. Set Target tile set: the tiles to be updated
4. iServer automatically shows scales in the list of Input tile set scale. Select the scales to updte and click Add.
5. Set Update bounds. By default, it is the maximum bound of the tiles
6. Click Start update.

Directional update

You could update the tiles which are being used by the map service component or the map service provider. Click Update tile on the configure page, so that it goes to the tile updating tool:

• For the map service component which starts the tiles, you can choose a tile type on the configure page, and click the Update tile link under the Storage Location.
• For the map service provider of the tile package (e.g., SMTiles), you can click Update tile link under the File Path on the configuration page.

Note

To make sure the data correctness, please consider the following aspects when updating tiles:

• Make sure that, in the tile source and the target data, tiles with the same map name should have the same tile styles, such as tile size, transparency, etc.
• Besides the requirements above, if the tiles are non-distributed storage tiles such as SMTiles, UGCV5, the map of Input tile set should be identical with the map of Target tile set.

Remove tiles with specified bounds

If a certain scope of the data needs to update, you can use clearCache. That is to say, delete the tiles in this bound first, and then create new tiles.

For example, if you want to delete tiles with the bounds Lon 120°~150° & Lat 30°~50°, please input the URL:

http://supermapiserver:8090/iserver/services/map-world/rest/maps/WorldMap/clearcache.rjson?bounds={"rightTop":{"y":50,"x":150},"leftBottom":{"y":30,"x":120}}。

It will return true when it is removed successfully.

Note: the clearCache will clear all tiles in this bound and tiles partially in this bound if you specify a geographic scope.