Embedding Pub/Sub mechanism into OGC web services to augment agricultural crop monitoring

摘要

The Pub/Sub, short for Publish-Subscribe, is a flexible mechanism perferred by many users who'd like to passively know the changes of situation. Once a new message is published by a provider, all the subscribers to the specific kind of messages will receive the message and make corresponding responses. In agricultural crop monitoring, such mechanism is very helpful in enhancing the efficiency of message spreading and farmers responding to sudden events. Thus, this paper tries to embed Pub/Sub mechanism into OGC web services which have been used in agricultural crop monitoring to search, access, describe and process the related data and information. This paper presents an initial framework to enable Pub/Sub in OGC web services via external supports. A Pub/Sub registry center is established for OGC web services and service users to subscribe and publish. Changes in OGC web services will be published as new messages to the registry. The registry will notify all the subscribers under the same theme with the message. A prototype is implemented for the framework. Some tests are made on a WCS, WMS and WFS. The results shows that through the prototype system, farmers or agricultural department can be timely notified about the changes such as new added remote sensing products about agricultural fields.