one receiver 104 and a memory 106 in a network 107 of other transmitters and receivers the network 107 may communicate via the internet protocol ip in conformance with traditional internet protocol use e g using the protocol system associated with the tcp ip protocol suite the transmitter 102 may include a graphic user interface gui 108 and keyboard or other input 110 that is connected to a computer the computer also shown as 108 acts as an intelligent agent on behalf of the user within the memory 106 a geospatial information database 112 may reside the memory 106 may be in any convenient location but preferably may be co located with the transmitter 102 be part of the transmitter 102 or be located in a secure environment such as a military tactical operations center toc the geospatial database 112 contains the available geospatial information which describes the geographic area 10 and at least the latest reported location identity and ip addresses of the various receivers 104 periodically the receivers 104 report their locations identities and ip addresses to the geospatial database on a frequency which may be selected by the user though the reporting need not necessarily be periodic since it may alternatively occur when a receiver 104 moves from its previously reported position beyond a threshold distance when the user wishes to send a message to recipients within a designated geographical area he enters the message into the transmitter 102 via the gui 108 or input device 110 since the transmitter 106 may be.