Location-based message distribution

1. A method, comprising:

receiving by a first processor, location messages having information transmitted from a plurality of second processors, wherein each location message specifies published geographical coordinates that indicate a geographical location of one of the second processors;

accessing a plurality of subscriptions to location topics in a storage arrangement by the first processor in response to receiving the location messages, wherein each location topic specifies subscribed-to geographical coordinates of a location;

determining by the first processor for each received location message, whether or not the published geographical coordinates match any of the subscribed-to geographical coordinates; and

transmitting from the first processor to one or more third processors identified by one or more of the subscriptions, respectively, each location message having published geographical coordinates determined to match the subscribed-to geographical coordinates of the one or more subscriptions.

2. The method of claim 1 , wherein:

each location message includes vehicle identification data for evaluation by the one or more third processors for selectively modifying phases of traffic lights; and

the transmitting includes transmitting the location messages to the one or more third processors that are disposed at one or more intersections for controlling the traffic lights.

3. The method of claim 2 , wherein:

a plurality of third processors are disposed at a plurality of intersections, respectively, the plurality of third processors includes the one or more third processors, and the plurality of intersections includes the one or more intersections;

for each intersection of the plurality of intersections:

a subset that includes multiple ones of the plurality of subscriptions defines an approach to the intersection; and

each location subscription of the subset identifies the respective third processor of the plurality of third processors disposed at the intersection; and

the determining includes determining whether or not the published geographical coordinates match the subscribed-to geographical coordinates of the multiple ones of the location subscriptions.

4. The method of claim 1 , wherein the subscribed-to geographical coordinates of each location topic include one latitude coordinate and one longitude coordinate, and the one latitude coordinate and one longitude coordinate are representative of a geographical area.

5. The method of claim 4 , wherein the geographical area is a rectangle.

6. The method of claim 5 , wherein the rectangle has first sides that are parallel to geographic lines of latitude and second sides that are parallel to geographic lines of longitude.

7. The method of claim 1 , wherein:

the subscribed-to geographical coordinates of each location topic include one latitude coordinate, one longitude coordinate, and one altitude value; and

the published geographical coordinates of each location message specify one latitude coordinate, one longitude coordinate, and one altitude value.

8. The method of claim 1 , wherein the receiving includes receiving by the first processor, location messages transmitted wirelessly from the plurality of second processors that are onboard a plurality of moving vehicles, each location message having location information that indicates a geographical location of one of the moving vehicles.

9. The method of claim 1 , wherein the transmitting includes transmitting each location message to the one or more third processors that are onboard a plurality of moving vehicles.

10. The method of claim 9 , wherein the receiving includes receiving by the first processor, location messages transmitted wirelessly from the plurality of second processors that disposed at a plurality of intersections, each location message having location information that indicates a geographical location of one of the intersections.

11. The method of claim 1 , wherein:

the published geographical coordinates are a version of actual geographic coordinates truncated from a first level of precision to a second level of precision; and

each location topic specifies subscribed-to geographical coordinates of a location in the second level of precision.

12. The method of claim 11 , wherein:

the subscribed-to geographical coordinates of each location topic include one latitude coordinate in the second level of precision, one longitude coordinate, in the second level of precision, and one altitude coordinate specified in a third level of precision; and

the published geographical coordinates of each location message specify one latitude coordinate, one longitude coordinate, and an altitude in the third level of precision that is truncated from a fourth level of precision of a measured altitude.

13. The method of claim 11 , further comprising truncating by the plurality of second processors, one or more levels of precision from the geographical coordinates having the first level of precision to generate the published geographical coordinates having to the second level of precision.

14. The method of claim 11 , further comprising:

receiving by a message server, the information transmitted from the plurality of second processors, wherein the information includes geographical coordinates having the first level of precision;

truncating by the message server, one or more levels of precision from the geographical coordinates having the first level of precision to generate the published geographical coordinates having to the second level of precision; and

providing the location messages to the first processor.

15. The method of claim 11 , wherein:

the receiving location messages includes receiving the published geographical coordinates specified as a character string;

the accessing subscriptions includes accessing the subscribed-to geographical coordinates specified as a character string; and

the determining includes comparing the character string that specifies the published geographical coordinates to the character string that specifies the subscribed-to geographical coordinates.

16. The method of claim 1 , wherein:

the receiving location messages includes receiving the published geographical coordinates specified as a character string;

the accessing subscriptions includes accessing the subscribed-to geographical coordinates specified as a character string; and

the determining includes comparing the character string that specifies the published geographical coordinates to the character string that specifies the subscribed-to geographical coordinates.

17. A system comprising:

an arrangement of one or more first processors;

a memory arrangement coupled to the one or more first processors and configured with instructions that when executed by the one or more first processors cause the one or more first processors to perform operations including:

receiving location messages having information transmitted from a plurality of second processors, wherein each location message specifies published geographical coordinates that indicate a geographical location of one of the second processors;

accessing a plurality of subscriptions to location topics in a storage arrangement in response to receiving the location messages, wherein each location topic specifies, subscribed-to geographical coordinates of a location;

determining for each received location message, whether or not the published geographical coordinates match any of the subscribed-to geographical coordinates; and

transmitting to one or more third processors identified by one or more of the subscriptions, respectively, each location message having published geographical coordinates determined to match the subscribed-to geographical coordinates of the one or more subscriptions.

18. The system of claim 17 , wherein:

each location message includes vehicle identification data for evaluation by the one or more third processors for selectively modifying phases of traffic lights; and

the instructions for transmitting include instructions that cause the one or more first processors to transmit the location messages to the one or more third processors that are disposed at one or more intersections for controlling the traffic lights.

19. The system of claim 18 , wherein:

for each intersection of the plurality of intersections:

a subset that includes multiple ones of the plurality of subscriptions defines an approach to the intersection; and

each location subscription of the subset identifies a respective third processor of a plurality of third processors disposed at a plurality of intersections, the plurality of third processors includes the one or more third processors, and the plurality of intersections includes the one or more intersections; and

the instructions for determining include instructions that cause the one or more first processors to determine whether or not the published geographical coordinates match the subscribed-to geographical coordinates of the multiple ones of the location subscriptions.

20. The system of claim 17 , wherein the subscribed-to geographical coordinates of each location topic include one latitude coordinate and one longitude coordinate, and the one latitude coordinate and one longitude coordinate are representative of a geographical area.

21. The system of claim 20 , wherein the geographical area is a rectangle.

22. The system of claim 21 , wherein the rectangle has first sides that are parallel to geographic lines of latitude and second sides that are parallel to geographic lines of longitude.

23. The system of claim 17 , wherein the instructions for receiving include instructions that cause the one or more first processors to receive location messages transmitted wirelessly from the plurality of second processors that are onboard a plurality of moving vehicles, each location message having location information that indicates a geographical location of one of the moving vehicles.

24. The system of claim 17 , wherein the instructions for transmitting include instructions that cause the one or more first processors to transmit each location message to the one or more third processors that are onboard a plurality of moving vehicles.

25. The system of claim 24 , wherein the instructions for receiving include instructions that cause the one or more first processors to receive location messages transmitted wirelessly from the plurality of second processors that disposed at a plurality of intersections, each location message having location information that indicates a geographical location of one of the intersections.

26. The system of claim 17 , wherein:

the subscribed-to geographical coordinates of each location topic include one latitude coordinate, one longitude coordinate, and one altitude value; and

the published geographical coordinates of each location message specify one latitude coordinate, one longitude coordinate, and one altitude value.

27. The system of claim 17 , wherein:

the published geographical coordinates are a version of actual geographic coordinates truncated from a first level of precision to a second level of precision; and

each location topic specifies subscribed-to geographical coordinates of a location in the second level of precision.

28. The system of claim 27 , wherein:

the subscribed-to geographical coordinates of each location topic include one latitude coordinate in the second level of precision, one longitude coordinate in the second level of precision, and one altitude coordinate specified in a third level of precision; and

the published geographical coordinates of each location message specify one latitude coordinate, one longitude coordinate, and an altitude in the third level of precision that is truncated from a fourth level of precision of a measured altitude.

29. The system of claim 27 , wherein the memory arrangement is further configured instructions that when executed by the one or more first processors cause the one or more first processors to perform operations including:

receiving information transmitted from the plurality of second processors, wherein the information includes geographical coordinates having the first level of precision;

truncating one or more levels of precision from the geographical coordinates having the first level of precision to generate the published geographical coordinates having to the second level of precision; and

providing the location messages.

30. The system of claim 17 , wherein:

the instructions for receiving location messages include instructions that cause the one or more first processors to receive the published geographical coordinates specified as a character string;

the instructions for accessing subscriptions include instructions that cause the one or more first processors to access the subscribed-to geographical coordinates specified as a character string; and

the instructions for determining include instructions that cause the one or more first processors to compare the character string that specifies the published geographical coordinates to the character string that specifies the subscribed-to geographical coordinates.