The map below shows surveillance devices we’ve mapped in Richmond. The directionality of security cameras and ALPRs is denoted by a triangular shadow.
Gunshot detectors are often placed such that they make an array to triangulate the location of gunfire via time difference of arrival, or the difference in times that each detector heard the sound. We can use this property to find gunshot detectors that haven’t been mapped: gunshot detectors need to be placed to make triangles.
Solid lines below indicate triangles that are likely complete, while dashed lines show triangles that are too big and likely missing points. Look for unmapped gunshot detectors in locations that complete an array of similarly-sized triangles.
Contributing
Don’t forget to first make an OpenSteetMap account!
If you’re out surveying, we suggest the DeFlock mobile app for mapping surveillance devices and the Every Door app for a simple way to map everything else.
Please see our tagging guidelines for further ways to map surveillance devices in OpenStreetMap.
