How Many Cops Does Your Local Government Have Per Resident?

Does Washington, D.C., have more cops than other cities? That’s the question I asked myself the other day after watching a patrol car drive down our quiet, residential street. I see patrol cars everywhere — much more often than I did previous cities like Houston and Austin. 

There’s a reason: Among the top 50 most-populous local governments, D.C. simply has more police officers per resident, according to the U.S. Department of Justice, which surveyed large police forces a few years ago. The city has about 670 cops per 100,000 residents, well ahead of Chicago, which was second with about 472 per 100,000. Houston had about 220, and Dallas had about 260. 

Of course, D.C. is the capitol and diplomatic center of the country, and it’s densely populated with pockets of high crime and poverty. So a large officer to resident rate is understandable. But it’s a bit surprising how much D.C.’s ratio eclipses that of other major cities. 

This chart shows the cities among the top 50 that have the highest per-resident officer ratio: 

Here are the data for all 50 cities plotted on a map made with TileMill. Larger symbols represent higher numbers of officers per 100,000 residents: 

See larger, interactive version

Data source: U.S. Bureau of Justice Statistics

A ‘Radical’ View of DC’s Demographics

I’ve been obsessed with William Rankin’s ‘radical cartography' site for more than a year. One map in particular — a detailed view of Washington, D.C.’s segregated neighborhoods — has stuck with me more than others over time.  

The map used 2000 Census data to show how black residents are clustered in northeast and southeast neighborhoods, while white residents live in the northwest. He also mapped poverty, income, crime and education — creating a stunning series of images about inequality in the city.

I don’t have Rankin’s cartography skills, but I’ve tried my best to update his race map, using similar colors and features, with the 2010 Census data. First, this map shows concentrations of black residents, who made up roughly half the city’s population in 2010, down 10 percentage points from the previous decade: 

This map shows where Hispanic residents are clustered: 

Here’s another version with all major race/ethnicity groups. The dots represent 25 residents per U.S. Census block: 

All the data used to make the maps can be download here

DC vs. Austin Weather: Part 2

Back in May I compared the weather in my former town, Austin, Texas, to my current home, Washington, DC. Now that I’ve lived through a summer here, I’ve revisited the topic with two simple line charts.

This first chart shows monthly averages. As you can see, Austin experienced 100-degree average high temperatures in July and August (with little rain), setting the stage for the destructive wild fires spreading around the city

View larger, interactive version

Here’s a day-by-day comparison: 

View larger, interactive version

Data source: Weather Underground | Download: Days | Months

'Hunkered Down' With Some DC Hurricane History

Using the NOAA’s cool hurricane tracker, I discovered that Washington, DC, hasn’t received a direct hit from a hurricane in recorded history. (And, of course, Hurricane Irene won’t pass directly over our city either).

It has, though, endured three tropical cyclones, all of which were unnamed: 

The first, a tropical storm from 1933, crossed directly over American University in northwest DC:

The second, in 1939, was a tropical depression. It moved through southeast DC along the Anacostia River near what’s now RFK Stadium: 

The last, in 1945, was something called an extratiopical cyclone. It clipped southeast DC: 


It’s getting windy outside. I should save this post before we lose power…

Charting DC 311 Calls

The D.C. government fielded nearly 430,000 service requests via 311 last year, according to records available in the city’s open data directory.

Residents asked to have potholes filled, snow and ice removed and defective parking meters repaired, among more than 100 other request categories

These simple charts, made with Google’s image chart tools, show when and where residents made those requests:

Calls By Weekday

Calls By Month

Calls By Month

* Ward 2’s figures are inflated by more than 100,000 requests to repair or disable parking meters. This could be because these neighborhoods have the highest population density in town, or because there’s heavy construction that requires meters to be turned off temporarily, or some other factor. 

Calls By Hour

Each requested is geocoded with latitude and longitude, so look for some maps soon…

D.C. Population, Crime by Political Wards

I’ve posted before about crime in Washington, D.C., a city I’m still working to understand demographically and geographically. Here are some maps I made this morning as part of that process.

First, here’s a look at population* by political ward (I live in Ward 5). Darker shades represent more residents. Notice that population is concentrated more heavily in the northern and northwestern wards in the city:  

This map shows population density (residents per square mile) by political ward. Darker shades represent increased density. Notice Ward 1, which is the most diverse in the city, also has the most density. It includes neighborhoods such as Adams Morgan, Columbia Heights and Shaw: 

Next, I mapped the numbers of major crimes reported in each political ward during 2008, 2009 and 2010. Darker shades represent more incidents. It’s clear that crime is more common in the southern and southeastern wards, which also have the poorest and most undereducated residents. 

First, homicides. Ward 8 had the most, 142, which is about a third of all killings in the district since January 2008: 

Robberies are also common in southeast, but look at densely populated Ward 1. It had more robberies than any other district during the three year period — 2,200.

Assaults with deadly weapons: 


This is interesting. Vehicle burglaries were most common in wards 1 and 2, perhaps because they are densely populated and, in Ward 2’s case especially, among the wealthiest: 

Source: DC Data, U.S. Census | Get crime data

* Population totals based on 2000 census. Ward-level population totals haven’t yet been compiled and released by the district government. 

In the Suburbs, I…

… should be buying gas, according to this map of D.C.-area gas prices. The lowest, in Maryland, are about $3.70 per gallon of regular gas. (The D.C. average is more than $4, but some stations are at or above $5).Larger symbols on this map, made with ArcGIS, represent higher prices: 

Here’s an interactive version: 

Source: | Map shapefiles | Data