@inthehands #CityOfCapeTown also engaged in this, probably for a nice kickback. Would've been way cheaper to commission a local outfit to reverse-engineer. It's just high-school trigonometry.

@inthehands It's also worth pointing out that even if their false positive rate was somehow zero, you still run into "you can only plot what you measure": they can't detect anything where the sensors aren't installed, so "no sensors" cannot be assumed equal to "no gunshots."

Any sort of heatmap for these things that doesn't have an obvious "there are no sensors here" overlay along with a corresponding heatmap of the sensor placement, should at this point be considered intentionally misleading data, IMO. It's the same thing as "almost any heatmap of the continental US is just a population density map."

Is “data redlining” a term people use? It should be.

/end