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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)

#91

Post by SafemapTecnolgs »

dang wrote: post #67
SafemapTecnolgs wrote: post #63

@dang or other HN mods - can you help me understand why this post was so rapidly downranked? It's now on the 6th page... it's got to be the highest upvoted yet lowest ranked post submitted today. As far as I can tell there were no flags or anything. Am I missing something here?

Two things: (1) it set off the flamewar detector a.k.a. the overheated discussion detector; (2) users flagged it. https://news.ycombinator.com/newsfaq.html

Thank you for helping to resolve the situation! Please disregard the email reply I sent as the issue was clearly rectified.

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

#94

Post by zeckalpha »

bufferoverflow wrote: post #2

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

And the whole WWII plane meme concern... this is where crimes were caught/reported, not where they occurred.

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

#95

Post by worstspotgain »

SafemapTecnolgs wrote: post #50
renewiltord wrote: post #33

Very cool! Car Break-In useful for “safe to park here?”

Thanks! Yeah unfortunately with cities like SF nowhere is truly "safe to park" but hopefully this helps people avoid the major hotspots!

It's actually quite safe to park in SF with two exceptions:

- With anything visible that might contain a valuable. Any devices in the trunk should be in Airplane Mode. If you're a tourist, don't park by a tourist trap.

- Any model with an oft-stolen catalytic converter, esp. Prius.

SF itself has higher-than-average tourist density, so it's a burgling destination too. But it's possible to park for decades and never have your car broken into.

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

#96

Post by davedx »

Sohcahtoa82 wrote: post #55
davedx wrote: post #25

Earlier quoted context omitted.

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…

I dunno, I'd think car break-ins would at least be a very important statistic. My wife and I will be spending a day in the Fisherman's Wharf area, and the statistics on car break-ins has me concerned, though a co-worker who lives in the Bay told me that if I'm parked in a parking garage, it's less likely I'll be a victim, as it's harder to smash-and-grab-and-go when you have to deal with a parking gate.

Yeah we parked across from the Exploratorium near there for several hours and it was fine, I didn’t think to consult crime heat maps before visiting, just followed standard common sense of not leaving visible ipads etc in the car.

What is the actual car break in statistic there?

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

#97

Post by vladvasiliu »

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…

I, as a tourist, would very much prefer being able to walk around looking at random things and relaxing instead of being on the lookout for people trying to steal my things or worse.

Also, when on a trip, getting my phone stolen, for example, is much more of a hassle than having it stolen on the street where I live. Bonus points for thieves actually going for bags and such, so now it's likely you'll need to pay a visit to your embassy or whatever to have your passport replaced, too. In the city where I live, if my ID gets stolen, I'm likely to have at least a different form at home, and I also pretty much know where and when to go to the authorities to try to obtain a replacement.

Speaking of SF, I have no idea if my country even has any kind of representation there, where it would be, how I would get there, and how long it would take to have temporary papers made up, especially without a phone or similar device.

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

#98

Post by JumpCrisscross »

mh- wrote: post #8
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…

I mean, I'd also be pretty interested in avoiding P(a crime occurs near you), especially as a tourist.

> I'd also be pretty interested in avoiding P(a crime occurs near you), especially as a tourist

What counts as nearby also scales with density. Down the street is nearby in the suburbs. In New York the next avenue block may as well be another town.

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

#100

Post by citrin_ru »

bufferoverflow wrote: post #2

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

Divided by population one of highest crime rate areas in the UK is Westminster because this are attracts a lot of tourists (some are targeted by pickpockets) but not much people live there (denominator is small). A better metric will be crime count divided by man-hours spent in the area per day. Such data unlikely exists in open access but mobile operators should be able to estimate it based on base station logs.
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