Recently I wrote about how a Los Angeles Police Dept. geocoding data glitch yielded inaccurate crime maps at LAPDcrimemaps.org and the database-powered network of hyperlocal sites, Everyblock.
On Apr. 8, Everyblock founder Adrian Holovaty blogged about the two ways his company is addressing the problem of inaccurate geodata.
- Latitude/longitude crosschecking. “From now on, rather than relying blindly on our data sources’ longitude/latitude points, we cross-check those points with our own geocoding of the address provided. If the LAPD’s geocoding for a particular crime is significantly off from our own geocoder’s results, then we won’t geocode that crime at all, and we publish a note on the crime page that explains why a map isn’t available. (If you’re curious, we’re using 375 meters as our threshold. That is, if our own geocoder comes up with a point more than 375 meters away from the point that LAPD provides, then we won’t place the crime on a map, or on block/neighborhood pages.)
- Surfacing ungeocoded data. “Starting today, wherever we have aggregate charts by neighborhood, ZIP or other boundary, we include the number, and percentage, of records that couldn’t be geocoded. Each location chart has a new “Unknown” row that provides these figures. Note that technically this figure includes more than nongeocodable records — it also includes any records that were successfully geocoded but don’t lie in any neighborhood. For example, in our Philadelphia crime section, you can see that one percent of crime reports in the last 30 days are in an ‘unknown’ neighborhood; this means those 35 records either couldn’t be geocoded or lie outside any of the Philadelphia neighborhood boundaries that we’ve compiled.”
These strategies could — and probably should — be employed by any organization publishing online maps that rely on government or third-party geodata.
Holovaty’s post also includes a great plain-language explanation of what geodata really is and how it works in practical terms. This is the kind of information that constitutes journalism 101 in the online age.
(NOTE: I originally published this post in Poynter’s E-Media Tidbits.)
LAPDcrimemaps.org has some recently revealed geodata flaws.
Crime maps are one of the most popular and (in urban areas) ubiquitous types of geo-enabled local news — and they’re a staple of the Knight News Challenge-funded project Everyblock. This data comes from local police departments — but how reliable is it?
On Sunday, the Los Angeles Times reported a problem with the Los Angeles Police Department’s online crime map, launched three years ago…
“LAPDcrimemaps.org is offered to the public as a way to track crimes near specific addresses in the city of Los Angeles. Most of the time that process worked fine. But when it failed, crimes were often shown miles from where they actually occurred.
“Unable to parse the intersection of Paloma Street and Adams Boulevard, for instance, the computer used a default point for Los Angeles, roughly 1st and Spring streets. Mistakes could have the effect of masking real crime spikes as well as creating false ones.”
Apparently the LAPD wast not aware of the error until alerted by the Times…
|Scene of Boulder’s 2008 Naked Pumpkin Run busts, plus two nearby real (violent) crimes earlier that same day.
UPDATE NOV 4. The names of the 12 busted streakers have been published, so I’m following up on this case via local courts…
On Halloween, as I wrote earlier, I went down to Boulder, CO’s Pearl St. pedestrian mall to check out the costumes — which are always spectacular — and to see the annual Naked Pumpkin Run. (Note: that link above goes to my blog post which includes a video containing nudity.) This loosely organized event has a lot of local fans.
The Naked Pumpkin Run is nothing more than that — sometime around 9-10 pm on Halloween, a bunch of people get naked, put jack-o-lanterns on their heads, and run en masse down the Pearl St. Mall. It’s not sexual, violent, dangerous, or threatening. It’s just silly. It’s unique. It’s fun. It’s exuberant. It’s positive and life-affirming.
And: It’s illegal.
Unlike in previous years, the Boulder police were out in force for this event, where they ticketed several runners for indecent exposure. Consequently, several fun-loving local folks may end up suffering life-altering public stigma as registered sex offenders.
The Colorado Daily posted this video of the event, including some footage of the busts:
Need some irony? All this happened less than 24 hours after two remarkably violent assaults, which occurred just a half-mile from the scene of the Naked Pumpkin Run busts.
Here are the details, as best as I’ve been able to gather them so far… Continue reading