A choropleth map is one in which polygons (such as census tracts, zip codes, states, etc.) are shaded in hues that correspond with the density of some phenomenon within each polygon. They are frequently used to display demographic data, and often used for crime data within such polygons as police districts, census tracts, and so forth. I don’t use them very often myself for some complex GIS-geek reasons, but you’ll find a couple of examples in the Chief’s Corner of choropleth maps.
I received an email yesterday from Mike Behm, the director of the Nebraska Commission on Law Enforcement and Criminal Justice (AKA the Crime Commission). Mike was letting the police community in Nebraska know that the Commission has launched a new application that generates a choropleth map of Nebraska’s 93 counties, based on either the offense rate or arrest rate. 
Like LPD, the Crime Commission has some good web-based tools for generating your own tables and statistics from the data that it collects. This mapping application is a nice addition to their offerings.
18 comments:
Yawn
7:07 -
Sometimes I even bore myself.
http://flowingdata.com/2010/01/21/how-to-make-a-heatmap-a-quick-and-easy-solution/
So the highest (per-capita) arrest rates are in extremely rural areas. Does this really surprise anyone?
I wish we could map murders (not rates) by legislative district. I heard that there are more murders in one leg. district than in all of the other 48 - combined - and it'd be nice to check the veracity of that claim.
10:04-
I don't think that's possible. Omaha, of course, has the majority of the murders in the State: 44 of 67 in 2008, for example. While District 11 has plenty of those, I don't think it's anywhere close to half. You could compare this map to this map. The Omaha World Herald's homicide map is for 2009, when murders in Omaha fell to 31. I don't know what the Statewide number for 2009 is, but because of the decline in Omaha, I imagine it's going to be somewhere around the low 50's.
I don't suppose you have the percentage of those 2009 Omaha murders which had a gang-affiliated victim, do you? I know it's not your jurisdiction, but I thought I'd ask. It would also be interesting to know what percentage of Omaha's (reported) home invasions had a victim with a drug history.
In any case, I bet you know right off the top of your head what percentage of Lincoln's reported home invasions had victims with an illegal drug history; what is it, something like 98 or 99%?
By the way, is there a probable cause issue with running a drug dog through all HIR crime scenes for a sniff?
Chief,
What are the stats on the motives for murder in the State? For instance: what percentage are Domestic? Stranger on stranger? During a robbery? Sexual? To cover up another crime? Just plain mental illness?
It would seem to me that knowing the motives and the conditions that create those motivations would be crucial to identifying and changing the conditions that create these hostile acts. By know the motivations behind these crimes various groups, civilian and governmental, can work on changing those conditions. Simple preventive maintainence (sic?).
Gun Nut
11:50-
Of the 2009 home invasions in Lincoln, we have evidence that 27 of 41 were drug-related. In almost all of the remainder, there is some suspicion. I haven't got any clue what Omaha's data would show, but I imagine the connection between drug histories and home invasions would hold most anywhere in the land. Yes, there would definitely be an issue with that: you would need a warrant.
Gun net:
I'd say in Lincoln's case, mental issues would be prevalent, followed by domestic violence. I can only recall three robberies of businesses that resulted in murders during my years--Marianne Mitzner (1975), Eugene Fields (1977) Gary Jones (2000). There have been a few non-business robberies that led to murder--Eugene Warren and Brandon Pickenpaugh come immediately to mind--where victims were set up for a ripoff, then killed in the process.
Chief,
This is a bit off topic but I was just wondering how many COLD CASE murders are still on the books in Lincoln?
Gun Nut
Gun Nut-
I assume by "cold case" you mean unsolved murders. Do you want me to go all the way back to John Sheedy? We also have a few cases, that we may never be sure about--is it a murder, suicide, accidental, or natural death?
In the past decade, there have been two murders in Lincoln that are still unsolved.
Chief,
Thanks for the reply to my Cold Case query. Recently I read the book WHAT PSALM SINGING SON OF A BITCH SAID THAT? written by Samuel Van Pelt. It was a very interesting book with a lot of anecdotes about the Lincoln judicial and law enforcement scene going back many years. I assume you know the Judge? I loved his book.
Gun Nut
Gun nut-
Of course. His Honor followed me into office as Lancaster County Sheriff--after my replacement lasted one day on the job. Pretty easy gig--I left the place in good shape.
Chief-Case of the two young boys found in the railroad tank car during the Nebraska State Fair in about 1973 or 1974; any disposition? Always wondered.
Thanks, 256
Off topic, but if more crimes were like the school bus theft I imagine your jobs would be much easier. Combine a stupid thief with a citizen getting involved, and it's aced!
"Of the 2009 home invasions in Lincoln, we have evidence that 27 of 41 were drug-related. In almost all of the remainder, there is some suspicion."
It would be nice to see a little info sidebar with a similar reminder, run alongside every home invasion robbery story in the local paper, and included in all home-invasion TV news stories. You wouldn't believe (or maybe you would) how many moderately-informed law-abiding citizens believe that home invasion victims are just like them, law-abiding and non-dealing citizens.
By the way, if you didn't actually name the victims, would you be able to have your PIO inform the press abut their drug-contact histories in any HIR press briefing, and mention the HIR-drug connection? The PIO could also mention when you were almost certain there was no drug connection (other than the robbers being dopers), which happens once in a blue moon, as with that elderly couple who were HIRed and beaten some time back.
256-
Jon Simpson and Jake Surber. William "Freight Train" Guatney was arrested, but the charges were subsequently dismissed, and he died.
3:43-
Job security.
4:03-
Yeah, the general public doesn't have the same magic 8 ball as the police officers and most readers of this blog. Unfortunately, you can't be trashing the victim in the press if you expect some cooperation. The reporters usuallly understand what's going on and know when there is more to the story, but a raised eyebrow doesn't come across in print, and and the ability of people to read between the lines isn't as good as you would hope.
cheif, polygons, followed by choroplephs. full seven/partial wedge. you need an check-up
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