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Copyright © 2013 Open Geospatial Consortium.
The schema automation activities in the OWS-9 initiative have specified and implemented an encoding rule for JSON see Clause 6.
have clarified and implemented the SWE Common 2.0 XML Schema encoding rule see 7.2,
have analyzed possibilities for generating SWE Common 2.0 record descriptions from schemas in UML see 7.3.
6 Support for JSON
6.1 Overview
The scope of the activity discussed in this Clause is to explore the generation of JSON Schema – or alternative means – for specifying JSON-based data exchange structures
from UML similar to the UGAS approach.
Figure 1 illustrates the conversion process. An organisation, in this example NGA, manages an application schema according to ISO 19109, in this example NGA TDS. This
application schema determines the structures in which data is captured and stored as datasets in spatial databases.
ShapeChange is used to derive representations from the application schema. In this case the XML Schema a GML application schema and JSON Schema consistent with the
GeoServices JSON feature model representations are shown. The process has been used for GML application schemas for many years now. The GML application schemas will
then typically be used to publish the data via an OGC Web Feature Service.
The capability for JSON Schema representations has been specified and implemented during OWS-9. In the JSON Schema variant that is consistent with GeoServices JSON
from the OGC candidate standard GeoServices REST API, the JSON encoded features would typically be published via a GeoServices REST API Feature Service.
Copyright © 2013 Open Geospatial Consortium.
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Figure 1 – Converting an application schema to implementation schemas
Figure 2 shows the test scenario where NGA TDS data in a database is provided in both representations, JSON via a GeoServices REST API Feature Service and GML via a Web
Feature Service. Both services use XtraServer from interactive instruments. The services are accessed with clients from other sources ArcGIS.com, ArcMap, Gaia. This provides
a range of clients with access to the same data via the service interface they support best.
