Friday, November 21, 2014

Geocoding crucial

The Director's Desk readership includes a lot of analysts and GIS aficionados. I'm going to geek out in this post, so unless you are among them, consider yourself forewarned.

Public safety analysts and technicians mine data from dispatch records, incident report, and other databases in order to work with these data in a GIS framework. The dots don't appear on the maps magically, though. The geocoding process uses software algorithms to convert the text description of an address into a point on a map. 

Geocoding is both art and science, and accuracy is important. If large numbers of events will not geocode, or geocode improperly, the validity of any analysis is compromised. It doesn't take much to throw things off, either, because geocoding errors are often not random. Rather, they tend to be systematic: the same address gets missed over and over, or a tiny error in a street reference file results in the same address getting incorrectly placed on the wrong side of a census tract boundary, evey single time. 

Because of this, accuracy of geocoding should be a top concern for those of us who manage GIS applications. The key is to understand what isn't geocoding properly, and to systematically correct as much of that is possible. You may not be able to prevent the occasional fat-fingered entry where someone inserted an extra zero in an address field, but if you can never properly geocode the street address of a local high school, you've got to figure out why and correct that. 

Here in Lincoln, we're geocoding a few hundred thousand police and fire incidents and dispatches annually. I watch the unmatched records closely, in order to monitor any consistent geocoding problems. So I was pretty pleased to see this geocoding history report for recent fire dispatches yesterday morning:

Hard to top that, in almost a thousand records that are updated twice daily. That's the Omega Group's Import Wizard software pictured in this screen shot, which manages the data import and geocoding from both police and fire records systems in Lincoln, in order to populate CrimeView and FireView applications.

My advice to analysts is not to be complacent even if you have a high hit rate. Keep an eye on your unmatched records, find the repeats, figure out why, and fix the problem whenever possible. 

Wednesday, November 19, 2014

Foiled by Facebook

An interesting case (B4-106047) early this morning caught my attention in today's police reports. Shortly after midnight, an officer was dispatched to a downtown bar, after an employee became suspicious of a customer's true identity. It seems the employee checked her ID to determine if she was of legal age, but noticed that the name on the ID and the name on the credit card presented for payment did not match.

The police were summoned. The customer told the investigating officer that the ID was hers, but the credit card was her mother's, which she had permission to use. The photo ID looked like her, but the officer wasn't completely certain. Lacking any evidence to the contrary, however, no further action was taken. Afterwards, the employees did a little research of there own, and found the social media profile of the name on the credit card. Sure enough, it was unmistakably the customer, who had apparently "borrowed" an ID from someone that looked similar enough to her that it wasn't obvious to the officer at the scene.

The customer had slipped out, so the bar employee notified the officer, and showed her what they had found. She then contacted the defendant by cellphone. She fessed up to the scheme, and voluntarily agreed to meet the investigating officer at police headquarters to receive her citations for minor attempt to purchase alcohol and providing false information to a police officer.

You can find most anything on the Internet these days. Nice work, Duffy's!

Monday, November 17, 2014

Learning curve

The blast of winter weather last week caught motorists in Lincoln off guard. Balmy temperatures in the 60s during the first week of November were followed by single digits last week, with a couple dustings of snow. It seems that every year there is a certain learning curve, as motorists try to adapt to winter driving conditions.

Tuesday morning's commute was light, due to the fact that government offices and financial institutions were closed for Veteran's Day, but Lincoln drivers managed to get involved in 84 traffic crashes nonetheless. It was not even measurable precipitation, but just enough to glaze the streets. On Saturday, a whopping 1.5 inches of snowfall resulted in 81 crashes: almost four times the daily average.

I noted an interesting pattern to the collisions when I did an hour-of-the-day analysis using CrimeView Dashboard. The first graph shows the distribution by time of day for crashes on Tuesday, November 11. The second graph is for Saturday, November 15.

As you can see, Tuesday's crashes spiked in a two-hour window during the morning drive-time, after which street conditions quickly improved. Saturday's crashes were spread more throughout the day. Notice the dip on Saturday at 1400 hours, when most Nebraskans were finding a TV in order to watch a football game that turned out to be something of a let down.

Time to refresh the basics: leave earlier, take your time, go easy on the gas when accelerating, keep a healthy following distance, anticipate your stops, and make sure you can see the spot where the tires of the vehicle ahead touch the pavement when you come to a stop in traffic. If you've been thinking the tread is getting a little worn, it would be a good time now to replace those tires and improve your grip.

Wednesday, November 12, 2014

Flyover country

Nebraska's are all familiar with the fact that millions of Americans living in big cities and on the coasts are geographically challenged. It happens like this: you encounter someone from Massachusetts in the airport lounge in Atlanta, and strike up a conversation. "Where are you from?" she asks. "Nebraska," you respond. "Oh," she says, "I love Las Vegas!"

There are, however, major advantages to living in flyover country, among which is that you generally can figure out east, west, north, and south--even up and down--quite a bit better than your fellow citizens in more populous places. Smug in the knowledge that Lincoln is actually the 72nd largest city in the USA, I simply smile at the misconceptions harbored by those who navigate by subway stops and freeway numbers.

So, I'm sitting in the living room yesterday morning, reading the news on my MacBook and encounter a bunch of links to news stories about the FBI's annual release of their statistical report, Crime in America. One of the links is to an online database at the Detroit Free Press. I'm always interested in these journalistic data projects, so I followed the link, and went to look up Lincoln--just to ensure the data was accurate.

Low and behold, Nebraska appears to have left the Union!

Monday, November 10, 2014

The F word

Dr. Samuel Walker, one of the most well-known experts on civil liberties and criminal justice in the United States, taught at the University of Nebraska at Omaha for over 30 years. His tenure overlapped my college career, and although I am a graduate of his department, I never had him as a professor. I don't always agree with Dr. Walker's positions, but last week he published a short paper which is spot-on.

It concerns the F word, and more broadly profanity and disrespectful language in general. This has no place in police interactions with the public, and I agree completely with Dr. Walker that it should be eliminated from the vocabulary. Profanity in public interactions is prohibited by policy, and I've dealt with several officers and deputies over this as a supervisor. Nonetheless, I'm not sure it has completely sunken in to everyone how corrosive it is to respect for the police.

We live in a culture where F-bombs are not uncommon, even in otherwise polite conversation. When it comes from a police officer, however, it has an entirely different connotation. I'm not na├»ve, and I'm not unfamiliar the salty language one hears in a squad room, and pretty tolerant thereof--so long as it is not racist, sexist, or homophobic--but this is way different than slinging profanity on the street and to the public.

All police officers need to practice self-control, even when confronted with people who are spewing the most hateful and vile language imaginable in their face.