Tile Format |
With the development of cache technology, SuperMap GIS series products are constantly developing and improving the generation of cache, and the accuracy of map cache is constantly enhanced.
Generally speaking, map caching mainly refers to map tiles, but starting from 7C products, the caching of map services includes new vector tiles and attribute tiles (outdated) in addition to the traditional raster tiles.
The production of map cache is mainly realized through the Distributed Tiling Service, which supports the segmentation of map data into tiles of various formats and storage, such as raster tiles in FastDFS, MongoDB, SMTiles, etc., vector tiles in SVTiles.
| Type | Tile Format | Storage Mode | Storage Location | Version Supported | Platform Supported | Distribution Method |
|
Raster tile |
MongoDB | MongoDB Distributed File System | The data is stored in the specified directory. See Installation and Configuration of MongoDB for details. The tiling result of the map is a tileset in the tile library. | Yes | Linux、 Windows | Support direct copy distribution between MongoDB systems |
| OTS (Obsolete) | OTS Distributed File System | Data is stored in Alibaba Cloud OTS storage service system. | No | Linux、 Windows |
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| MBTiles | SQLite Database | output path \sqlite\*.mbtiles files, such as China__256X256_PNG_T.mbtiles. | No | Linux、 Windows | Direct copy file distribution | |
| SMTiles | SQLite Database | output path \sqlite\*.smtiles file, such as China_-1085299276_256X256_PNG.smtiles. | No | Linux、 Windows | Direct copy file distribution | |
| UGCV5 | Local Disk File Directory | output path \cache\, see Version of SuperMap UGC Format Map Tiles for details. | No | Linux、 Windows | Direct copy file distribution | |
| S3 Object Storage | /{bucket name}/{map name}/{map name}.sci file | No | Linux、 rh-implicit_p ? Windows | Direct copy file distribution | ||
| GeoPackage | SQLite Database | output path \sqlite\*.gpkg file, such as ChinaProvinces_4326_256X256_PNG.gpkg | No | Linux、 Windows | Direct copy file distribution | |
| Vector tiles | SVTiles | SQLite Database | output path \sqlite\*.svtiles file, such as China_1023937971_256X256.svtiles | No | Linux、 Windows | Direct copy file distribution |
| MongoDB | MongoDB Distributed File System | The data is stored in the specified directory. See Installation and Configuration of MongoDB for details. The tiling result of the map is a tileset in the tile library. | Yes | Linux、 Windows | Support direct copy distribution between MongoDB systems |
As shown in the table above, for different tile formats, we can summarize the following characteristics:
Map tiles that split and store all layers in the map as raster images, with support for MongoDB , OTS (obsolete) distributed storage, SMTiles and MBTiles format , SuperMap UGC Format, GeoPackage format.
The SuperMap UGC format is a traditional map tiles format that is common among SuperMap products, and map tiles of the same version can be used universally. The "UGCV5" tile type supported by the distributed tiling service supports the 5.0 version of the original cache and the compact cache.
In addition, the format of map tiles supports PNG, PNG 8, JPG_PNG, JPG, WebP. If PNG is selected and the number of current map color values is less than or equal to 256, SuperMap iServer automatically saves images in PNG8 format to save storage space.
Tile and store the specified vector layer in the map in the form of vector tiles. Support SVTiles format , MongoDB distributed storage.
In the application of map services, in addition to providing users with access to browse maps, there is also a practical need to provide users with operations such as querying, selecting, and highlighting. In this case, it is necessary to provide users with the above functions through element services. Just as map services require caching technology to improve access speed, feature services also need to pre generate tiles from vector data to enhance client rendering speed. Therefore, Vector Tile was born. When storing vector data, its volume is smaller than that of map tiles, making it more suitable for expressing terrain features with high timeliness requirements in maps, such as POI information, route information, etc. Common online map services, such as Google Maps and Baidu Maps, use grid tiles as the base map and overlay vector tiles.