Triggers for Actions

Actions allow you to perform processing on temporal data to enhance your data analysis capability. You can define trigger criteria for actions, so that only data meeting the trigger criteria will have the action applied.

Types of Triggers

Actions can be triggered using the following criteria:

• Always on action: This action will be applied to every data message of that particular message definition type.
• Attribute only action: The action will be applied to a data message that meets the specified attribute criteria. For example, you might want to use the filter action to filter hurricane data for data messages where the wind speed is greater than 75 miles per hour.
• Location only action: Apply this action to data messages that meet some geographic criteria. For example, you could filter the data messages to only allow hurricane data that is over land.
• Attribute and location action: This action uses both the attribute and location triggers when applying an action.

Location Triggers

Location triggers are used to execute actions when certain spatial criteria are met. Location triggers can be used with any action.

Location triggers require a set of polygon features to do a spatial comparison with. The user must browse to a polygon feature class when setting up the location trigger. You can use location triggers independently to execute an action, or you can use them together with an attribute trigger.

There are several types of location triggers provided:

• Intersects: This trigger executes an action when a feature in an incoming data message intersects with features in a polygon feature class.
• Not Intersects: This trigger executes an action when a feature in an incoming data message does not intersect with features in a polygon feature class.
• Arriving: This trigger executes an action when a feature in an incoming data message indicates the arrival of a tracked object within a polygon feature class. This happens when a feature intersects a polygon in the feature class, and the previous feature in the track didn’t. This differs from the Intersects location trigger because the action can only be triggered once each time a track enters the polygon. After the trigger is activated for a track, the track must report at least one event outside the polygon to reset the trigger before it can be activated again.
• Departing: This trigger executes an action when a feature in an incoming data message indicates the departure of a tracked object from within a polygon feature class. This happens when a feature doesn’t intersect a polygon in the feature class, and the previous feature in the track did. This differs from the Not Intersects location trigger because the action can only be triggered once each time a track leaves the polygon. After the trigger is activated for a track, the track must report at least one event inside the polygon to reset the trigger before it can be activated again.
• Track Crosses: This trigger executes an action when a feature in an incoming data message indicates that a tracked object has crossed the boundary of features in a polygon feature class. This happens when a track point in a data message intersects a polygon in the feature class, and the previous point in the track didn’t, or vice versa. The Track Crosses trigger also executes an action when two consecutive points do not intersect a polygon but the track line connecting them does.