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Show HN: Play with an interactive heatmap of SF crime (and other cities)

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Re: Show HN: Play with an interactive heatmap of SF crime (and other cities)

#72

Post by s1mon »

calibas wrote: post #37

Also serves as a map of where to find prostitutes. Apparently, that's the area around South Van Ness & 20th St in SF.

Capp Street is the center of the issue - so much so that permanent bollards have been added to cut down on customers circling the blocks looking for people selling themselves.

https://missionlocal.org/2024/04/barricaded-capp-street-park...

Re: Show HN: Play with an interactive heatmap of SF crime (and other cities)

#73

Post by s1mon »

This is very cool.

I turned on all the types of crime and a weird set of diagonal darker regions appeared in the avenues. Either this is some weird artifact of the geocoding or there's some really strange magnetic fields or something affecting crime.

Re: Show HN: Play with an interactive heatmap of SF crime (and other cities)

#75

Post by roughly »

dheera wrote: post #47
bufferoverflow wrote: post #2

You need to divide crime counts by population density. Otherwise you're just plotting population density.

Yes and no. Not dividing by population density ~ Probability I will become a crime victim by travelling through that area Dividing by population densitiy ~ Probability that I would be a crime victim if I live in that area

> Probability I will become a crime victim by travelling through that area

Still not that. P(you’re the victim) = crime count/potential victim count.

Population density may not be the right number for the denominator, but you need something in there.

Re: Show HN: Play with an interactive heatmap of SF crime (and other cities)

#76

Post by roughly »

echelon wrote: post #26
paraboul wrote: post #16

Earlier quoted context omitted.

Not really, since your chance of being a victim is divided by the number of people in the area.

> Not really, since your chance of being a victim is divided by the number of people in the area. Depends on behavior. If I stay in my room all day, I don't contribute to your divisor. If Jack Dorsey doesn't walk around alone past midnight, he's not absorbing the same risk quotient either.

> If Jack Dorsey doesn't walk around alone past midnight, he's not absorbing the same risk quotient either.

Jack Dorsey is a weird motherfucker and a real outlier for this example. He used to walk to the Twitter office every day and generally looks and dresses like someone well outside his economic strata. I would not be surprised to find “midnight solo perambulations through the tenderloin” among his hobbies.

Re: Show HN: Play with an interactive heatmap of SF crime (and other cities)

#77

Post by roughly »

SafemapTecnolgs wrote: post #48
jeffbee wrote: post #46

The location of the police stations seems influential. I know in Berkeley crimes without a firm location get geocoded to police HQ. Do you think that might be affecting these maps?

Interesting, thanks for the info. I think it hopefully should be OK for the currently supported cities. Lots of cities have 0,0 as the geo point for crimes without points, which we filter out. For others such as SF, it looks like the police HQ is in Mission Bay which doesn't seem to have a high crime rate for any category. This info would also hopefully be included in the dataset disclaimers, and we didn't see this i…

SF has several police districts and district stations - may be worth checking against those, too: https://www.sanfranciscopolice.org/your-sfpd/sfpd-stations/s...

Re: Show HN: Play with an interactive heatmap of SF crime (and other cities)

#79

Post by burningChrome »

davedx wrote: post #25
rachofsunshine wrote: post #6

Earlier quoted context omitted.

That's probably not the correct analysis, because the number you're trying to estimate is not P(a crime occurs near you), it's P(you will personally be the victim of a crime). Crime rate over density won't necessarily do that either (since the population density of a primarily commercial+touristy area, e.g. Fisherman's Wharf, is << the number of people who are present there on a given day), but neither does raw count…

As a tourist in SF recently I was interested in seeing the whole city, warts and all, and I did. I don't really understand why as a tourist you'd want to use this map for a short trip, unless you were going somewhere that's a literal war zone. Most cities just aren't statistically dangerous for a tourist unless you go out looking for trouble. You're much better off applying common sense than digging through digital m…

>> If I was looking for somewhere to live then it would be more interesting I think.

When I was looking at places to live in South Carolina, Florida and places in the Northwest like Oregon and Idaho, it was interesting to see some of the crime maps and grades these sites gave for crime.

In small coastal towns in Florida, they had small populations and were essentially tourist towns or inhabited by "snow birds" people who live in Northern states who live there during the Winter. Several of the places got D's or F's for crime. I was just shocked, but reading the footnotes, they made it clear that the numbers could be skewed because of the transit population or other factors like Spring Break revelers who come down, get in fights, people get assaulted, or sometimes killed and suddenly a small town's crime rate goes through the roof because of an outlier event that year.

It just made me leery about any statistics you see online with cool heat maps or grades they give to certain areas.

As an aside, the same thing was evident in small rural towns in the mountains in Idaho as well which also got poor grades for crime. It aligns more with your comment, it you go looking for trouble, chances are, you're going to find it.

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