Caching in general offers advantages in contrast to live access to the data.
- Reduction of traffic between client and server
- Fast access to cached data on the client side
- Cache is possible for vector and raster data
- Support of offline capabilities
- Snapping on vector data on the client side
There are three types of caching, which are possible in GeoMedia Smart Client:
- Caching on demand
The standard caching method is the fastest possible access to your data of the three mentioned above. Only at the start the cache gets checked. The cache is published by the administrator (How to generate cache can be read here) and the main cache is located on the server.
The client only requests a tile if the tile isn't in the local cache or a newer tile is on the server.
The second method is the Live access to the data. This possibility is the slowest of all options, because every tile gets created if it is requested. So on the client side the tile gets created and if you pan around or whatever the tiles which are visible in GeoMedia Smart Client gets newly created no matter if the tile got created before.
Caching on demand
The last option, which is available is Caching on demand. This hybrid method is located between Cache and Live in respect of performance caused by the communication between the server and the client everytime the map got panned. The client checks if there is a newer version of the tile on the server. This can be caused by two aspects:
- Publishing new tiles (for example: new data is available)
- A tile (for example: attributes of a tile) got edited in the database
For example: New data is available and you set the Feature loader to Caching on demand. Then the data gets a timestamp. If the timestamp of the feature is newer than the timestamp of the tile, the map is panned to, the tile gets an update. If new data is published there are no restrictions in respect of Data sources.
For example: You edit something on the tile (for example attributes), then the tile gets an update too if the map gets panned to the tile with new or edited attributes. There are some restrictions in respect of this method. It is only possible to edit the tile within the GeoMedia Smart Client or with a workflow. If you edit the attribute(s) in GeoMedia Pro you have to define a database trigger to transfer the changes to the database. In respect of Data sources you are restricted to the database systems Oracle or SQLServer (not GeoMedia WebMap (!!!))