It seems pretty obvious the system they selected was inadequate for what they were hoping to accomplish.
When you talk about a range of 500 feet, is that a 250 or a 500 foot radius?
I'm not sure if my calculation is correct, but in order to cover an area of 17 sq miles, I come up with about 7900 400 cameras/sensors if we're talking about a 500 foot radius and each are placed 1000 feet apart (((17 4 miles*5280 feet)-1000)/1000 feet)^2). A lot more if we bring that down to 250 feet.
Then again, they may only have wanted to cover the more "urban" part of the city, but that's not clear from the story.
With 18 devices and a 500 foot radius, the largest area they could have had continuous coverage over is about one square mile.
I'm pretty sure I read that ShotSpotter has an approximate cost of ~$100K/sq mile.
According to Alains cost analysis, Sentri is ~$250K/sq mile. What are the distance claims of ShotSpotter sensors? Does ShotSpotter use more sensors/sq mile?
I'm curious how the two products compare.... and I'm also wondering why - according to the data above - Sentri is 2.5x less expensive per sq mile.
The obvious answer is that it doesn't work well... but I'm curious if the two companies have similar technical approaches or if they are using different technologies alltogether - which might point to why the cost/sq mile of each product is so different.
IPVMU Certified | 02/09/14 06:40pm
I live in this town and drive these streets often. The cameras are a huge unsightly big brother mess on the corners of SOME of the city streets. Even the dumbest criminals take notice to where they are being watched and where they think they can get away with things. All these cameras did was move the criminal behavior to the other corners. While I am not familiar with the implementation done by the city, I think the Sentri system was more Video Surveillance with an add-on of Gunshot detection. ShotSpotter which the city wants installed now, is a more vast array of microphones, of which have no camera tie in, rather a simple Gunshot location on a map, and it doesn't need to be installed directly in the areas of the crime prone street corners. The two systems sound completely different. However its still shame on Sentri for even trying to tout this as a city wide application for gunshot detection if they did that. That should have been made very clear it was secondary to the video and almost like a free add-on as its effectiveness in actually being able to provide usable video is next to none based on gunshot detection. They could be touting that it will alert based on the sound heard, but actually saying it will provide evidence, is going way overboard.
What the city needs to do is analyze how many crimes of gunshot nature occurred within theses cameras ranges to really determine if the hardware was effective or not. That is what there not saying in any of the interviews.
Looking into the numbers even at $14k per camera, if the stated cost is just vendor spending and no internal or monthly cost allocation which I doubt, multiple cameras on a pole, in a city wide rollout the cost is not uncommon just for the video alone.
IPVMU Certified | 02/09/14 09:36pm
Shot spotter is a sound locating app only, it has no cameras that tie in, so naked or not it wouldnt matter.
Sentri yes maybe, but much like there are not many shootings from criminals in the police station, i cant see that even the dumbest would have a shoot out under a police monitored surveillance camera. I am sure there idiots out there that would but sounds like it at least alerted to the 5 or 6 of them of which is the same thing shot spotter would have done.
I am for portable and hidden if it has a gun shot detector on it then thats a plus.
Right now this city is is crime infested and has lost all faith in the police, NO ONE talks not even when the victim is related to them, cameras will be essential not a sound locating device that will rely on people to speak up.
IPVMU Certified | 02/09/14 10:47pm
I live in a city with no Gunshot Detection, but lots of guns. I asked a couple of Policemen if finding the origin are of where shots are fired is a problem. They said sometimes, but more often they get calls dispatching them to an area on account of an engine backfire. So false alarms are a problem, but one that isn't likely fixed by a system like this.
They both said one method they use is to follow the barking dogs after shots are fired. They generally lead them close to the source, but in no case is reaction very rapid. Policeman aren't trained to go spontaneously roll into a gunfight unless they know more about what is going on first.