Table Joining Service Overview

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TJS Operations

TJS operations are the means by which a client can interact with a TJS implementation. Each TJS operation supports either service discovery, data discovery and access, or the joining of attribute data to a spatial framework.

All TJS instances must implement the service discovery operation (GetCapabilities). TJS instances may choose to implement the data discovery and access operations, or the data joining operations, or both. When implementing any of these groups of operations, all of the operations in the grouping must be implemented.

Service Discovery Operations (mandatory)

Data Access Operations (optional)

TJS includes four operations that support the retrieval of geographic attribute data. The actual delivery of attribute data is performed via the GetData operation. Several related metadata operations return information about the attribute data that the TJS can deliver: DescribeFrameworks, DescribeDatasets, and DescribeData. The responses to these operations return framework, dataset, and attribute metadata that describe the data available from the service instance. These responses can be used to populate service registries. If the TJS supports data access, then all of these operations are mandatory.

Data Joining Operations (optional)

TJS includes three operations that support the joining of attribute information with its geometry. The merging of data is performed via the JoinData operation. The related DescribeJoinAbilities operation returns information about the spatial frameworks to which attributes can be joined, while the DescribeKey operation returns the contents of the framework key field for a framework dataset. If the service instance supports data joining, then all of these operations are mandatory.