organizations W3C, IETF, OMG, AMIC and others, generally offering expertise related to spatial issues and receiving expertise necessary to ensure that OGCs standards
framework is consistent with other IT standards frameworks. - Accommodate independently developed implementations of a service and many
independently provided instantiations of different types of services; - Accommodate a wide range of data policies e.g., data access and data use policies;
- Be vendor and data neutral; - Be data content format independent.
5.2.2 Services, interfaces and operations
Key definitions for the Service Framework are:
- A Service as a distinct part of the functionality that is provided by an entity through interfaces,
- An Interface as a named set of operations that characterize the behavior of an entity, - An Operation as a specification of a transformation or query that an object may be
called to execute. Each operation has a name and a list of parameters.
Figure 2 - Service definition relationships
A service may be expressed at various levels of granularity. A coarse-grained collaboration may be refined to produce a service that has a finer granularity. This is
Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved.
7
accomplished by expanding one or more operations from a high level collaboration into distinct lower level services, one for each operation.
An instance of a service may be associated with a specific instance of a dataset, or it may be a service that can be used to operate on multiple, unspecified datasets. The first case is
referred to as a tightly coupled data and service. The second case is referred to as loosely coupled service. Service operations can be associated with data classes data
type or with instances data set.
5.2.3 OWS service framework
The OWS Service Framework OSF identifies services, interfaces and exchange protocols that can be utilized by any application. OpenGIS Services are implementations
of services that conform to OpenGIS Implementation Specifications. Compliant applications, called OpenGIS Applications, can then plug into the framework to join
the operational environment.
By building applications to common interfaces, each application can be built without a- priori or run-time dependencies on other applications or services. Applications and
services can be added, modified, or replaced without impacting other applications. In addition, operational workflows can be changed on-the-fly, allowing rapid response to
time-critical situations. This loosely coupled, standards-based approach to development results in very agile systems—systems that can be flexibly adapted to changing
requirements and technologies
User Interfaces Client Applications
OWS Clients OWS Context
Web Portals
OWS Clients OWS Context
User Interfaces Client Applications
OWS Clients OWS Context
Web Portals
OWS Clients OWS Context
Business Processes
Data, Service, Style, Feature
Registries
CSW
Portrayal Services
WMS, FPS, CPS
Processing Services
WCTS, WPS
Workflow Services
WNS, BPEL Business Processes
Data, Service, Style, Feature
Registries
CSW
Data, Service, Style, Feature
Registries
CSW
Portrayal Services
WMS, FPS, CPS
Portrayal Services
WMS, FPS, CPS
Processing Services
WCTS, WPS
Processing Services
WCTS, WPS
Workflow Services
WNS, BPEL
Data Access
Data Services
WMS, WFS, WCS
Sensor Web
SOS, SPS, SAS
OpenLS
Tracking
Digital Rights Management
GeoDRM Data Access
Data Services
WMS, WFS, WCS
Data Services
WMS, WFS, WCS
Sensor Web
SOS, SPS, SAS
Sensor Web
SOS, SPS, SAS
OpenLS
Tracking
OpenLS
Tracking
Digital Rights Management
GeoDRM
Digital Rights Management
GeoDRM
Figure 3 - OWS Service Framework
8
Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved.
