A method, system, and article of manufacture enable the use of location based applications (LBA). A location server (LS) on a wireless network receives trigger information from a LBA that is located outside of the wireless network. The trigger information defines a source locatable, spatial information (defining spatial criteria for a target locatable), a notification flag (describing) an interaction between the source locatable and the spatial criteria), and temporal information (defining a time period the trigger will be active). The LS determines if the triggers are active based on the temporal information and obtains updated locations if the trigger is active. Active triggers are evaluated to determine if a trigger alert has been caused by the locatables interacting with each other pursuant to the spatial information and notification flag. A location answer is pushed to the LBA if a trigger alert has been caused.