Direct Use

User Story

A system (often in the mobile/handheld computing environment) must provide tiled coverage data to support a number of client applications running on the device. These applications perform various visualization and/or analytical operations. To make most efficient use of the limited storage space available on the system, the data must be stored in a single repository and shared by the client applications. To reduce development costs, the data should be served through a simple, common interface. The server must be able to handle concurrent requests for the same data without issues.

Preconditions

1. Coverage data stored in a SQLite database (perhaps a GeoPackage extension)

Use Case

• Multiple client applications issue WCTS requests for required tiles
• Server brokers the requests while maintaining the single allowed connection to the database
• Server returns tile responses

Update (One-way replication)

User Story

A server system must support a client system that operates in an environment with disconnected/intermittent/limited connectivity and therefore must have a local repository of tiled coverage data to support the Direct Use use case (see above). The client is pre-loaded with a relevant subset of available tiled coverage data. The server is then updated with new tiles. Upon request, the server must provide updates to the client.

Preconditions

1. Client has an existing coverage repository containing a relevant subset of available tiled coverage data
2. Server receives updated tiles through an external process

Use Case

• Client issues WCTS (or WPS?) request for updated tiles, using its current manifest as an input.
• Server returns response containing updated tiles (Note: WMTS does not support responses with multiple tiles at this time)
• Client updates local repository with updated tiles

Alternate

• Client issues WCTS request for available tiles
• Server returns manifest of its current tile offering
• Client determines which tiles have been updated and issues WCTS request for those tiles. Would be better if client could issue a single request for multiple tiles (not supported by WMTS)
• Server returns response containing updated tiles
• Client updates local repository with updated tiles

-- JeffYutzler - 19 May 2015