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I declare this bulk data visualization day! NY Times Upshot blog today posted a cool visualization called Where We Came From, State by State. They charted how Americans have moved between states since 1900. The charts were compiled using Census microdata obtained from ipums.org at the University of Minnesota Population Center. Great state-by-state migration flows there. If they’d have asked me, I would have told them also about the free migration data available from the Internal Revenue Service. While the IRS data only goes back to 1990, it’s much more robust in that it gives county-by-county as well as state-to-state migration inflows and outflows. (By the way, do I need to remind our readers that none of this visualization would be able to be done without the US Census?!)
The visualization is a circle cut up into arcs, the light-colored pieces along the edge of the circle, each one representing a state. The arcs are connected to each other by links, and each link represents the flow of people between two states. States with longer arcs exchange people with more states (California and New York, for example, have larger arcs). Links are thicker when there are relatively more people moving between two states. The color of each link is determined by the state that contributes the most migrants, so for example, the link between California and Texas is blue rather than orange, because California sent over 62,000 people to Texas, while Texas only sent about 43,000 people to California. Note that, to keep the graphic clean, I only drew a link between two states if they exchanged at least 10,000 people.
The U.S. Census Bureau has a Data Visualization Gallery where they post weekly “explorations of Census data.” Some of these strike me as unnecessary (does adding animation to the map of population density around Interstate 5 add any value to the data?), but strangely cool; (I will never be able to drive north from San Diego again without remembering this map!). At the very least, the site is a showcase for the data and (I hope) an inspiration to budding data visualizers!
Hat tip to LAist, a website about Los Angeles, that has a brief story (4 Cool Ways Of Visualizing Local Census Data) that links to some of their favorites that show how the population has been changing in Los Angeles and California relative to the rest of the country.
The 10 most segregated urban areas in America, By Daniel Denvir, Salon (Mar 29, 2011). “Slide show: The new census numbers provide a sobering reminder of how separate white and black America still are.”
Decades after the end of Jim Crow, and three years after the election of America’s first black president, the United States remains a profoundly segregated country.
That reality has been reinforced by the release of Census Bureau data last week that shows black and white Americans still tend to live in their own neighborhoods, often far apart from each other. Segregation itself, the decennial census report indicates, is only decreasing slowly, although the dividing lines are shifting as middle-income blacks, Latinos and Asians move to once all-white suburbs — whereupon whites often move away, turning older suburbs into new, if less distressed, ghettos.
One great way to get your head around a large government dataset is to view it using Google Earth. I went on a hunt for the most interesting, striking and geography based government data sets currently available in the KML format used by Google Earth. There is a large gallery of tours and layers available from Google Earth’s site, including some based on government data – but I wanted to look beyond them.
Here are eleven data sources (in no particular order) that have KML files ready and waiting for you to download. For some of these you will need to read the instructions associated with the KML to understand what you are looking at and what special features are enabled. Some have multiple datasets within a single KML file — others include animations. Often when you open them in Google Earth they will start out with either a helpful note or a built in graphical key.
- USDA Forest Service: MODIS Active Fire Mapping Program: View fire detection data and incident information
- USGS Earthquake Hazards Program: real-time earthquake data (updated every 5 minutes!), geologic features and virtual tours of historic earthquakes.
- FEMA Flood Hazards: Stay Dry provides basic flood hazard map information from FEMA’s National Flood Hazard Layer for specific addresses while NFHL (National Flood Hazard Layer) appears to be a more general application that displays flood hazard zones, floodways, base flood elevations, cross sections and coastal transects and much more.
- NASA: Goddard Scientific Visualization Studio: provides various visualization layers including Tectonic Plates Boundaries and African Fires during 2002. Dig through the various categories, there is a lot here.
- Nasa Jet Propulsion Laboratory OnEarth: multiple options are available for viewing daily updated views of earth from satellites. Very striking!
- gCensus: provides access to data from the 2000 US Census. The site lets you browse for various elements of data and generate a KML file you can then view via Google Earth.
- Air Quality Now: provides current and forcasted air quality conditions for locations across the USA. It is a product of a partnership of multiple US Government agencies.
- National Weather Service: has a full page of KML layers related to all aspects of weather – past, present and predicted.
- National Gallery of Art: Afghanistan Hidden Treasures from the National Museum: visit Aï Khanum, Tillya Tepe, and Begram—that and examine Afghan Treasures
- National Park Service: National Register of Historic Places: provides Google Earth layers per region of the USA that mark historic places.
- District of Columbia Data Catalog: provides a wide range of data about our nations capital. You must supply some simple data to identify yourself before downloading these KML files. This is just a taste of what various regional governments are providing. Give your home state, district or territory’s website a look to see if you can find KML data available.