1. Introduction· This work consists in the deployment (and un-deployment) of SQL scripts in transactional WPS servers at runtime.· For the concrete implementation, we used the geoprocessing SQL scripts provided by GearScape and the 52º North implementation of the transactional extension of the WPS services (WPS-T).
2. GearScape geoprocessing language· SQL92 standard implementation together with the OGC simple feature access specification· Independent from format, file type and location of source data.· Local execution
2. Advantages· SQL language is simpler than imperative languages.· SQL scripts can be encapsulated as black boxes and reused later by using wizards.· SQL language can be seen as a language to speak about geoprocesses.
3.1. WPS· Set of standard operations for the publication and execution of any geoprocess via web.· Defines 3 operations: - GetCapabilities - DescribeProcess - ExecuteProcess
3.2. WPS-Transactional· WPS standard does not define how to deploy (and undeploy) geoprocesses at runtime.· 52º North Initiative proposes an extension with 2 specific operations for that purpose: · DeployProcess · UndeployProcess· 52º North Initiative itself has developed an implementation of the extension.
4.1. Description· WPS-T implementation has been provided the ability of understanding GearScape geoprocessing language.· As a result, the server can describe and execute existing SQL scripts as well as deploy new SQL scripts at runtime.
4.2. Workflow· Create an SQL script with (or without) GearScape editor.· Deploy the script in a running instance of the 52N WPS-T server implementation.· Reuse the geoprocess by executing it using any WPS client.
4.2. Workflow (1/3)Geoprocesses WPS-Transactional User
4.2. Workflow (2/3) GearScape SQL scriptsGeoprocesses WPS-Transactional DeployProcess User
4.2. Workflow (3/3)Geoprocesses WPS-Transactional User
4.3. Sample scenario- As proof of concept 2 scenarios have been created: · Reusability · Interoperability- The screencasts can be found in the Documentation section in www.fergonco.es/gearscape
Future work- Raster data integration in the SQL engine.- Sextante algorithms integration in the SQL engine.- Parallel computing in the SQL engine.