[HN Gopher] Show HN: Play with an interactive heatmap of SF crim...
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Show HN: Play with an interactive heatmap of SF crime (and other
cities)
Author : SafemapTecnolgs
Score : 88 points
Date : 2024-08-07 14:56 UTC (8 hours ago)
(HTM) web link (safemap.io)
(TXT) w3m dump (safemap.io)
| bufferoverflow wrote:
| You need to divide crime counts by population density. Otherwise
| you're just plotting population density.
| xnx wrote:
| Depends on how the map is being used. If I'm looking to avoid
| traveling through neighborhoods with a high robbery risk (e.g.
| as a tourist), I'd prefer absolute numbers vs. per capita.
| rachofsunshine wrote:
| 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.
| mh- wrote:
| I mean, I'd also be pretty interested in avoiding P(a crime
| occurs near you), especially as a tourist.
| chatmasta wrote:
| Yeah there are only 24 hours in a day, so the right
| metric might be density of crimes in an area per hour.
| Even if I'm not the victim of a robbery, I don't really
| want to be watching it from across the street.
| davedx wrote:
| 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 maps of
| (reported) crimes.
|
| If I was looking for somewhere to live then it would be
| more interesting I think.
| Sohcahtoa82 wrote:
| 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.
| whimsicalism wrote:
| if you're really worried, don't leave anything in your
| car and don't lock it
| almogo wrote:
| This seems like the best use-case, finding a place to
| live in a city. As a SF-area resident I know the
| Tenderloin is a no-go zone, but besides that not much.
| This is a good tool to see which neighborhoods to focus
| my search on in the apartment-finding process.
| burningChrome wrote:
| >> 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.
| SafemapTecnolgs wrote:
| Thanks for checking out the site and for the feedback. It's
| definitely something we're looking into.
|
| It's kind of an interesting question though because it somewhat
| varies by crime category. Take car break ins, for instance -
| this is more of a constant factor than a population density
| scalar because the number of parking spots is generally fixed
| on a per-block basis rather than scaling with population
| density.
|
| I think we might try to give users the option of dividing by
| population density but allow them to toggle this on/off.
| aeturnum wrote:
| Parking turnover probably scales with population density. One
| of the reasons parking is more expensive in big cities is to
| encourage people to move their cars sooner. Smaller cities
| will have more cars that never move, where larger ones will
| have fewer.
| giantg2 wrote:
| If it's about movement, then population density might not
| be the best factor either. You might need some other way to
| see the number of humans moving through a given area. Stuff
| like office buildings have higher populations during office
| hours, but wouldn't be caught in "population" metrics.
| yashap wrote:
| Yeah, I think having it as an option is the way to go. Though
| I'd personally have it default to per-capita, as I do think
| that correlates closer with actual risk. To illustrate with
| an extreme example, an area with 10 burglaries per 100 people
| is clearly a way higher burglary risk place to live than an
| area with 20 burglaries per 10,000 people.
| chatmasta wrote:
| The number of parking spots may be static, but the number of
| potential thieves scales with population density.
| rogers12 wrote:
| Does it really? Some classes of crime have been narrowed
| down to the same 50 individuals. You can't model car break-
| ins as everybody in the area rolling the dice on getting a
| taste for breaking glass and grabbing things.
| chowchowchow wrote:
| it scales with a factor of less than 1.0 but yes it
| scales. For instance the number of thieves could be given
| by the ratio .001 * population.
| postalrat wrote:
| That depends if people care more about crime happening to them
| or crime happening around them.
| whimsicalism wrote:
| this is not a map of population density it's pretty clear just
| the SRO strip/TL and then the two mission bart stations
| abeppu wrote:
| But it's interesting to see that this is not true for _all_
| crime categories. E.g. car break-in hotspots are by Fisherman
| 's Wharf and the side of Alamo Square with the Painted Ladies
| -- i.e. prime tourist locations.
|
| However, I suspect there are some basic data errors upstream
| of this visualization tool that also limits its usefulness.
| E.g. 'rape' has a giant hotspot centered at the south side of
| the intersection of 8th and Mission ... which is site of a
| city Adult General Assistance office. I am guessing these are
| being tagged with the location where the victim gave a
| report, not the location where the crime happened.
| Spivak wrote:
| Is it actually true that crime in an area increases
| proportionally with population? Why would it?
|
| Extremely high density but near zero crime would be inside a
| large office building.
| jazzyjackson wrote:
| there's such a thing as a "target rich environment" but I
| always look at these maps as "where people are", college
| campuses, tourist attractions, crime is high because the
| number of marks is high, its a coincidence if many people
| happen to live there too
| spacebanana7 wrote:
| It's an important truth that walking a mile in a high
| population density area puts you at a higher crime risk than
| walking a mile in a medium or low population density area.
| paraboul wrote:
| Not really, since your chance of being a victim is divided by
| the number of people in the area.
| echelon wrote:
| > 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.
| roughly wrote:
| > 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.
| aeturnum wrote:
| It's the opposite - right? There are more gross crimes in the
| high-density area, but your chance of suffering one is much
| lower (all else being equal). Trying to apply statistics
| directly like this is generally inaccurate, but to the degree
| the numbers say anything it's the opposite of what you say.
| spacebanana7 wrote:
| Fair point, it's more complicated than I originally
| thought.
|
| Density increases the number of potential criminals you
| pass but also increases the number of alternative victims
| they could target.
|
| If you're a uniquely attractive/visibly wealthy personal
| walking home from a night out then the risk of passing more
| criminals dominates the advantage of alterative targets.
| After all, there's nothing really competing with you.
|
| However, if you look like normal person but happen to have
| a million dollar watch in your pocket then you're
| conceivably safer in a city. Because there'd be so many
| alternative victims who may be more attractive targets than
| you. Compared to the countryside robber who only gets a
| single target per night.
| aeturnum wrote:
| There's also a lot of evidence that a given individuals'
| chance of being the victim of a particular crime derives
| from their social situation. Most people who regularly do
| crime are used to doing crime in a way they can repeat,
| and those crimes most often target locals and people from
| the same social sphere. There are also plenty of factors
| that lead to the targeting of tourists or wealthy people,
| but most crime victims are poor and live in similar
| conditions to the person committing a crime against them.
|
| Obviously this isn't every crime! People do have unlikely
| crimes happen to them all the time! Just that they're
| statistical anomalies and the population level statistics
| will mislead you about how high your risk is.
| copx wrote:
| The population density in Singapore is much higher than in
| Detroit. Guess where you are more likely to become the victim
| of a crime..
| jeffbee wrote:
| And you have to use daytime, not resident, population
| estimates, or a combination.
| dheera wrote:
| 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
| binary132 wrote:
| Not necessarily, people may (or may not? maybe it's regional)
| be more likely to victimize strangers.
| roughly wrote:
| > 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.
| muststopmyths wrote:
| Nicely done. Longer term historical data would be nice too, for
| comparison or trends. It should be available as these sorts of
| crime maps were all the rage 10-15 years ago.
|
| Personally, I would prefer that the crimes filter panel
| automatically hide itself when I click on the map after selecting
| my filter.
|
| Kudos.
| SafemapTecnolgs wrote:
| Thanks! Yeah, we definitely plan to add long term historical
| data and give users the option of diving deeper into the
| trends. Should be in the very near future. Thanks for the idea
| of auto-hiding the sidebar on a map click - that's very
| intuitive. Will probably push an update later today to add
| this.
| whimsicalism wrote:
| The TL is high-crime and the Mission bart stations have crime.
| Not exactly shocking to anyone who has lived here
| aeturnum wrote:
| I was interested to see that there are only really prostitution
| arrests in the middle of the mission!
| whimsicalism wrote:
| yes, shotwell and capp are a pretty obvious corridor if you
| want to witness it ever
| microtherion wrote:
| It's interesting to see how certain crimes (e.g. Assault and
| Robbery) have hotspots that map perfectly onto BART stops (16th &
| Mission, 24th & Mission).
| whimsicalism wrote:
| it's not surprising if you've ever lived in that area
| autoexecbat wrote:
| It is somewhat surprising actually. Presumably if there's an
| actual hotspot that police would be ever-present in the area
| until it dilutes out
| whimsicalism wrote:
| > police would be ever-present in the area
|
| you live in the area? because your comment doesn't sound
| like it
| duskwuff wrote:
| Possibly because the crimes are occurring aboard the train, so
| the exact location of the crime is unclear?
| whimsicalism wrote:
| probably not - the areas outside these bart stations are
| known as crime hotspots
| burkaman wrote:
| FYI none of your images are loading for me, they all return 301s
| repeatedly until the browser gives up.
| SafemapTecnolgs wrote:
| Hmm, thanks. Hopefully this doesn't include the map itself.
| Would you kindly provide the browser / OS combo you are
| operating? Will try and look into this.
| burkaman wrote:
| Firefox, Windows. The map loads fine, just the icons don't
| work.
| delichon wrote:
| Location based danger zone notifications would be helpful.
| "Warning: You are entering an area with a large number of
| reported muggings."
| whimsicalism wrote:
| or a warning every time you get into your car "Warning:
| locations like these have a significantly higher fatality rate"
| SafemapTecnolgs wrote:
| Stay tuned for some exciting feature launches in the near
| future :)
| delichon wrote:
| Please let me configure it so that I can play Kenny Loggins'
| Danger Zone as my notification.
| mindwork wrote:
| There is an app called Citizen that notifies you about crime
| happening near you in real time
| gilmore606 wrote:
| Damn, the police should start using that app!
| shaftway wrote:
| _Takes phone out of pocket to see what the notification was_
| tariverdiev1789 wrote:
| Awesome job, any chance of extending this to Europe? (Like Paris)
| SafemapTecnolgs wrote:
| Thank you! We are definitely interested in expanding to as many
| cities and countries as possible. We focused on large US cities
| with good datasets for this MVP, but depending on how things
| go, we will hopefully be expanding to cities across the world
| very soon.
| renewiltord wrote:
| Very cool! Car Break-In useful for "safe to park here?"
| SafemapTecnolgs wrote:
| Thanks! Yeah unfortunately with cities like SF nowhere is truly
| "safe to park" but hopefully this helps people avoid the major
| hotspots!
| hyuuu wrote:
| where did you source your data?
| SafemapTecnolgs wrote:
| Public datasets. You can view the sources for each city by
| expanding the "Data Sources" tab in the sidebar menu.
| calibas wrote:
| Also serves as a map of where to find prostitutes. Apparently,
| that's the area around South Van Ness & 20th St in SF.
| s1mon wrote:
| 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...
| autoexecbat wrote:
| Thanks for making this, it would be helpful if the city
| boundaries weren't so closely observed, most people don't care
| where the exact city lines are but have more of a feeling for the
| general metropolitan area as a blob
| dheera wrote:
| I wish that too but it seems their data sources are the cities
| themselves so those cities don't report things outside their
| jurisdiction.
| mckn1ght wrote:
| Pretty wild that you can intuit the city boundary by using the
| car break-in stat, it's the most evenly and widely distributed
| one I saw.
| jeffbee wrote:
| 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?
| SafemapTecnolgs wrote:
| 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 in any of the
| datasets we use.
|
| But thanks for the info, this is great to know for any
| potential future expansions. If you see any cases where this
| might be happening for the currently supported cities, please
| don't hesitate to get into contact with us :)
| roughly wrote:
| SF has several police districts and district stations - may
| be worth checking against those, too:
| https://www.sanfranciscopolice.org/your-sfpd/sfpd-
| stations/s...
| w10-1 wrote:
| Great work!
|
| - The maps are pretty and scale nicely. The clarity and
| granularity of text is appreciated.
|
| - The controls are excellent. I might put the copy and help in
| the same single title/menu panel (without "viewing:" as obvious)
|
| Some other features I found myself wanting:
|
| - Visually bound the map so you can see when it can't be moved in
| a direction. Think about what to do when the control panel is
| open and the user is trying to drag the map to see what's under
| the panel (instead of closing the panel).
|
| - ability to sort data drill-down by number, to look at most
| prevalent
|
| - using gradients for data starts to break down at low numbers. I
| wonder if you can start putting dots under some threshold
|
| - time-range delta heat-maps: 2023 car break-ins vs 2022 (where
| green is improvement, red is worsening, and intensity is size of
| delta)
|
| - surfacing qualitative aspects of data sources: one or many
| (only police?); and perhaps user feedback on quality of data
|
| - curate super-categories, e.g., capturing all cocaine-related
| offenses, or distinguishing the stacked charges (loitering in the
| area of ...) from the operative ones (dealing), or crimes against
| (visiting?) strangers vs locals or friends. The data sources have
| their own arcane categorizing logic, and it's rarely what users
| actually want.
|
| - color-code user-specified combinations: prostitution + drugs vs
| either alone
|
| - Most of these relate to the kinds of questions users can answer
| with the maps, so if you have a (user-contributed?) panel with
| questions and their associated configuration sets, it would be
| very powerful and sticky.
|
| - Then it would be nice to apply the same configuration-set to
| different cities, and perhaps to see some comparison across
| cities
|
| Some things I wouldn't do:
|
| - All-caps, tm? ok, but...
|
| - I think putting safety under quality of life makes the product
| a bit less polarizing and hence more popular - which means adding
| other quality-of-life measures (e.g., zoning
| (residential/retail/manufacturing), cost/sf for housing,
| walkability scoring) E.g., it would be interesting to know which
| retail districts are super-safe.
| SafemapTecnolgs wrote:
| @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?
| dang wrote:
| 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
| nasaeclipse wrote:
| Damn, wtf is going on at Little Saigon and that Park hotel?
| floren wrote:
| It's right smack in the Tenderloin
| s1mon wrote:
| 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.
| GrowthStein wrote:
| ITT: How not to be victim of crime?
|
| Solution: Don't move or go to the SF.
|
| Problem solved! Looks like many smart finds can't comprehend
| this.
| breck wrote:
| Do you have a version of this, but with positive data? For
| example, spots with great weather, or where acts of kindness
| frequently happen, or lots of photos get taken (so excellent
| views). Might be fun!
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