| 摘要 |
A geographical alert system creates an alert for a user-defined geographical area, detects a change to a feature stored in a map-related database, identifies whether the changed feature falls within the user-defined geographical area, and sends a notification to a user when the changed feature of the map-related database falls within the user-defined geographical area. To set up a geographical alert, an alert editor retrieves map data from a map-related database via an alert engine and displays the map data in a visual display to a user. The user then selects a geographical area that the system will automatically monitor for changes. The user may also specify a feature type, and an alert notification type for the alert. The alert engine then processes the user- specified geographical area into geographical area data and stores an alert and its corresponding geographical area data, feature type, and alert notification type in an alert database. When a change in the map-related database is detected, the alert engine obtains the geographic coordinate point data associated with the change and determines whether the geographical coordinate point data associated with the change falls within the geographical area of the stored alert in the alert database and if so, determines if the feature of the changed feature matches the feature of the stored alert. If the feature and geographical coordinate point data of the change corresponds to the feature and geographical area data of the stored alert, then the alert engine transmits an alert to the user using the alert notification type attributes of the stored alert. |
