Systems and methods for generating geofences
The present disclosure relates generating a geofence based on messages received periodically from a plurality of vehicles. A candidate geofence is approximated based on vehicle stoppage data obtained from a datalog of messages. For a given candidate geofence, additional stoppage data is obtained to identify additional vehicle stoppages. The locations of these additional vehicle stoppages are binned to a corresponding geospatial tile. A relatively large cluster of contiguous geospatial tiles form a geofence that may be transmitted to a client device.
1. A system comprising:
a processor; and
a memory coupled to a processor, the memory comprising a plurality of instructions, when executed, cause the processor to:
access a datalog comprising location samples and speed samples for a plurality of vehicles;
identify vehicle stoppages derived from the datalog, each vehicle stoppage corresponding to a respective stoppage location;
determine a candidate geofence based on a cluster of vehicle stoppages being within a predefined diameter, and further based on the size of the cluster exceeding a predetermined threshold of stoppages;
associate each vehicle stoppage within the candidate geofence to a corresponding tile;
for each tile, determine a respective number of vehicle stoppages;
identify a contiguous cluster of tiles, wherein each tile within the cluster has a respective number of vehicle stoppages that exceed a predetermined threshold count; and
generate a geofence based on the boundary of the contiguous cluster of tiles, wherein the processor is configured to generate the geofence by determining that the contiguous cluster of tiles is the largest among a plurality of contiguous clusters of tiles within the candidate geofence.
2. The system of claim 1 , wherein the memory comprising the plurality of instructions, when executed, cause the processor to:
receive messages periodically from each of the plurality of vehicles, each message comprising a location sample and speed sample for a corresponding vehicle; and
aggregate the messages received from each of the plurality of vehicles to generate the datalog.
3. The system of claim 1 , wherein the processor is configured to identify the set of vehicle stoppages by determining whether the number of consecutive speed samples that indicate no speed for a vehicle exceeds a threshold stoppage time.
4. The system of claim 1 , wherein the processor is configured to determine the candidate geofence by:
identifying a tile within a first tile system, according to the size of the cluster exceeding the predetermined threshold of stoppages; and
applying the predetermined diameter that surrounds the tile.
5. The system of claim 4 , wherein the processor is configured to associate each vehicle stoppage to the corresponding tile using a second tile system, the second tile system comprising tiles that are smaller than the tiles of the first tile system.
6. A computer implemented method comprising:
determining a candidate geofence based on a cluster of vehicle stoppages derived from a datalog, the datalog comprising location samples and speed samples for a plurality of vehicles, wherein determining a candidate geofence based on a cluster of vehicle stoppages derived from a datalog further comprises determining whether a threshold stoppage time is exceeded by the number of consecutive speed samples that indicate no speed for a vehicle;
accessing the datalog to identify a set of vehicle stoppages within the candidate geofence;
associating each vehicle stoppage in the set to a corresponding tile;
determining a respective number of vehicle stoppages for each tile;
identifying a contiguous cluster of tiles, wherein each tile within the cluster has a respective number of vehicle stoppages that exceed a predetermined threshold count, wherein identifying the contiguous cluster of tiles, comprises:
identifying a plurality of contiguous cluster of tiles; and
selecting the contiguous cluster of tiles as the largest among the plurality of contiguous cluster of tiles; and
generating a geofence based on the boundary of the contiguous cluster of tiles.
7. The method of claim 6 , further comprising:
receiving messages periodically from each of the plurality of vehicles, each message comprising a location sample and speed sample for a corresponding vehicle; and
aggregating the messages received from each of the plurality of vehicles to generate the datalog.
8. The method of claim 6 , wherein
determining the candidate geofence comprises:
identifying a tile based on a size of the cluster exceeding a predetermined threshold of stoppages and
applying a predetermined diameter that surrounds the tile to define the boundary of the candidate geofence.
9. The method of claim 6 , wherein associating each vehicle stoppage in the set to the corresponding tile comprises determining which hexagonal tile defined in a tile map contains the location associated with the vehicle stoppage.
10. The method of claim 6 , further comprising transmitting the geofence to a client device.
11. One or more non-transitory computer-readable, non-volatile storage memory comprising stored instructions that are executable and, responsive to execution by a computing device, the computing device performing operations comprising:
storing a datalog comprising location samples and speed samples for a plurality of vehicles;
identifying a tile of a first tile size that contains a threshold number of vehicle stoppages, the number of vehicle stoppages being derived from the datalog;
identifying a set of vehicle stoppages within a candidate geofence defined around the tile;
associating each vehicle stoppage in the set to a corresponding tile of a second tile size;
determining a respective number of vehicle stoppages for each file of the second tile size;
identifying a contiguous cluster of tiles of the second tile size, wherein each tile within the contiguous cluster has a respective number of vehicle stoppages that exceed a predetermined threshold count; and
generating a geofence based on the boundary of the contiguous cluster of tiles.
12. The one or more non-transitory computer-readable; non-volatile storage memory of claim 11 , wherein the second tile size is smaller than the first tile size and wherein the candidate geofence comprises a diameter greater than the first tile size.
13. The one or more non-transitory computer-readable, non-volatile storage memory of claim 11 , wherein the computing device further performs operations comprising:
receiving messages periodically from each of the plurality of vehicles, each message comprising a location sample and speed sample for a corresponding vehicle; and
aggregating the messages received from each of the plurality of vehicles to generate the datalog.
14. The one or more non-transitory computer-readable, non-volatile storage memory of claim 11 , the number of vehicle stoppages is derived from the datalog by determining whether the number of consecutive speed samples that indicate no speed exceeds a threshold stoppage time.
15. The one or more non-transitory computer-readable, non-volatile storage memory of claim 11 , wherein identifying the contiguous cluster of tiles of the second tile size comprises:
identifying a plurality of separate contiguous clusters of tiles; and
selecting the contiguous cluster of tiles as the largest among the plurality of separate contiguous cluster of tiles.
16. The one or more non-transitory computer-readable, non-volatile storage memory of claim 11 , wherein associating each vehicle stoppage in the set to the corresponding tile of the second tile size comprises determining which hexagonal tile defined in a tile map contains the location associated with the vehicle stoppage.
17. The one or more non-transitory compute readable, non-volatile storage memory of claim 11 , wherein the computing device further performs operations comprising transmitting the geofence to a client device.