Friday, April 26, 2013

Easy maps

I wrap up the series this week of "quick wins": tips for a new crime analyst, looking for some projects that can be spun up fairly rapidly and at low cost.

Maps are useful for visualizing crime, which explains why police officers have been sticking pins in maps since the early 19th century. The human eye is a powerful instrument, able to discern information from a map that would be far more difficult to conceptualize in a list, table, or stack of paper. These days, geographic information systems (GIS) enable some very sophisticated analysis and visualization. Jessica, the new crime analyst at the Grand Island Police Department, understands this, and it was her exploration of GIS software that caused her to contact me in the first place.

Implementing GIS for crime analysis is a very worthwhile undertaking, but will require some significant time and resources.  In the meantime, though, some simple yet useful maps can be produced using free and easy tools. This has changed dramatically in the past few years. For a new analyst who has yet to acquire the software and training she will need for geographic analysis, these free services could be used in the interim to produce some simple maps of interest to officers.

Two good examples are cartodb and batchgeo. These services let users drag-and-drop tabular data that contains addresses onto a webpage, which geocodes the data and produces a credible map in a matter of seconds. The free version usually has some limitations to encourage you to spring for the pro version (such as the ads in this sample), but the free service could still have a new analyst producing a useful map or two every week.  As an example, I went to the Fargo Police Depaartment's website, screen-scraped the dispatch data from April 1st, dropped it into batchgeo, and created this map in less than five minutes of traffic crashes on April Fool's Day in Fargo. It's interactive: pan, zoom, try Pegman, click on an icon.

View April 1 Crashes in a full screen map

You can also build maps for free with Google My Maps, ArcGIS online, and others. You could make a quick map, take a screen shot, and paste it into a bulletin, or onto a PowerPoint slide to provide a visual cue to officers to go along with the text.  In Grand Island's case, they can create basic maps within their records management system, and they already have a public-facing crime map, as they participate in from the Omega Group.  

Like any other Ciy whose data is published to, Grand Island officers could download the CrimeView NEARme app for Android or iOS, and have a pretty useful tool even though it would be displaying the public data until and unless they signed up for the real McCoy. Those data, even though mighty basic and cleaned for public consumption, still have some value to police officers.  

The Series:

Impromptu visit
Weekly slideshow
A place of your own
Better bulletins
Easy maps


Anonymous said...

I used to enjoy your blog allot more a few years ago. It seems that you have turned your focus on what is going on in the community to tech. I would like to see more community related posts.


Tom Casady said...


Who was it that said, "Sometimes I even bore myself."? Oh, that was me.

ARRRRG!!!! said...

Maybe this will liven things up a bit.

Anonymous said...

I can think of tho seemingly unrelated words that will prompt more discussion:

Potholes. Arena.