DC vs. Austin Weather: Part 2

By Matt Stiles | | Topics: Uncategorized

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

By Matt Stiles | | Topics: Uncategorized

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

By Matt Stiles | | Topics: Uncategorized

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…

Mapping D.C. Schools

By Matt Stiles | | Topics: Uncategorized

UMBC professor Lou Paladino made this interesting map that visualizes academic performance by Washington, D.C., school districts. Darker cool colors represent higher scores; darker warm colors represent lower scores. This shows that the separation of population in D.C. by race, poverty and crime also translates to schools: 

Download data

D.C. Population, Crime by Political Wards

By Matt Stiles | | Topics: Demographics

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…

By Matt Stiles | | Topics: Uncategorized

… 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: washingtondcgasprices.com | Map shapefiles | Data

DC vs. Austin Weather

By Matt Stiles | | Topics: Uncategorized

I love Austin, but my biggest complaint about Texas’ capitol city is the oppressive summer heat. And when I say summer, I mean April to October. Today’s high temperature is forecast to be 98 degrees, for example. 

A pleasant surprise in my new city, Washington, D.C., is that I’m actually experiencing an extended spring, with average high temperatures in the lower 70s for the last several weeks. Today’s high is supposed to be 71 degrees. 

While it surely will be humid in D.C., I don’t expect 30-plus days above 100 degrees, which isn’t uncommon in Austin. Weather data reinforce my hope. This interactive line chart shows the average high temperatures in both places by month. Sorry, Austin. 

Made with Google Visualization API | Source: The Weather Channel

Data: [AustinD.C.]

D.C. Census Drops (Finally)

By Matt Stiles | | Topics: Uncategorized

The U.S. Census Bureau today released redistricting data for the District of Columbia, a city that at first glance remains quite segregated — at least in terms of where people live. These quick maps visualize the percentage of black residents by census tract in 2000 and in 2010. 

First, 2000:

Now for 2010. Notice that some neighborhoods are becoming more diverse, but not that many. Fewer than I expected, actually, given all I’ve heard about gentrification in D.C., where I moved last week. 

(More to come).

Sources: U.S. Census Bureau, IRE | Data: csv, ESRI shp

D.C. Homicides

By Matt Stiles | | Topics: Uncategorized

The Washington, D.C., official data catalog is a rich source for information about the nation’s capitol. Users can download dozens of free GIS products as well as datasets related to city functions (311 service requests, permits, etc.) in relatively clean tables.

For today’s visualization I downloaded some 31,000 serious crime incidents in 2010, and then uploaded them to Google Fusion Tables, a free online database manager with powerful querying and visualization tools. The data were already geocoded, so I filtered the table for homicides and made this simple map (click the photo to see a full-screen interactive version): 

View an interactive map with all crimes, not just homicides. 

Sources: D.C. Data Catalog, Google Fusion Tables | Raw Data: CSV