• Using Census survey data properly

    April 11, 2014  |  Statistics

    The American Community Survey, an ongoing survey that the Census administers to millions per year, provides detailed information about how Americans live now and decades ago. There are tons of data tables on topics such as housing situations, education, and commute. The natural thing to do is to download the data, take it at face value, and carry on with your analysis or visualization.

    However, as is usually the case with data, there's more to it than that. Paul Overberg, a database editor at USA Today, explains in a practical guide on how to get the most out of the survey data (which can be generalized to other survey results).

    Journalists who use ACS a lot have a helpful slogan: "Don't make a big deal out of small differences." Journalists have all kinds of old-fashioned tools to deal with this kind of challenge, starting with adverbs: "about," "nearly," "almost," etc. It's also a good idea to round ACS numbers as a signal to users and to improve readability.

    In tables and visualizations, the job is tougher. These introduce ranking and cutpoints, which create potential pitfalls. For tables, it's often better to avoid rankings and instead create groups—high, middle, low. In visualizations, one workaround is to adapt high-low-close stock charts to show a number and its error margins. Interactive data can provide important details on hover or click.

    If you do any kind of data reporting, whatever field it's in, you should be familiar with most of what Overberg describes. If not, better get your learn on.

  • Bracket picks of the masses versus sports pundits

    April 11, 2014  |  Statistics

    NCAA bracket picking

    Stephen Pettigrew and Reuben Fischer-Baum, for Regressing, compared 11 million brackets on ESPN.com against those of pundits.

    To evaluate how much better (or worse) the experts were at predicting this year's tournament, I considered three criteria: the number of games correctly predicted, the number of points earned for correct picks, and the number of Final Four teams correctly identified. Generally the experts' brackets were slightly better than the non-expert ones, although the evidence isn't especially overwhelming. The analysis suggests that next year you'll have just as good a chance of winning your office pool if you make your own picks as if you follow the experts.

    Due to availability, the expert sample size is a small 53, but it does appear the expert brackets are somewhere in the area of the masses. Still too noisy to know for sure though.

    If anything, this speaks more to the randomness of the tournament than it does about people knowing what teams to pick. It's the same reason why my mom, who knows nothing about basketball or any sports for that matter, often comes out ahead in the work pool. The expert picks are just a point of reference.

  • High-detail maps with Disser

    April 10, 2014  |  Mapping

    Detailed building map

    Open data consultancy Conveyal released Disser, a command-line tool to disaggregate geographic data to show more details. For example, we've seen data represented with uniformly distributed dots to represent populations, which is fine for a zoomed out view. However, when you get in close, it can be useful to see distributions more accurately represented.

    If the goal of disaggregation is to make a reasonable guess at the data in its pre-aggregated form, we've done an okay job. There's an obvious flaw with this map, though. People aren't evenly distributed over a block — they're concentrated into residential buildings.

    So Disser combines datasets of different granularity, so that you can see spreads and concentrations that are closer to real life.

  • Independent coffee shops and community

    April 9, 2014  |  Mapping

    Independent coffee shops

    As part of the You Are Here project from the MIT Media Lab, an exploration of independent coffee shops in San Francisco:

    Independent coffee shops are positive markers of a living community. They function as social spaces, urban offices, and places to see the world go by. Communities are often formed by having spaces in which people can have casual interactions, and local and walkable coffee shops create those conditions, not only in the coffee shop themselves, but on the sidewalks around them. We use maps to know where these coffee shop communities exist and where, by placing new coffee shops, we can help form them.

    Each dot is a coffee shop, and the shaded spots around the dot represent the areas nearest each shop. It's an interesting, more granular contrast to coffee chain geography and provides a better sense of a city's layout.

    See also the same idea applied to Cambridge. I imagine there are more cities to come, as the data is gleaned from the Google Places and Google Distance Matrix APIs.

  • Extract CSV data from PDF files with Tabula

    April 8, 2014  |  Software

    Tabula

    Tabula, by Manuel Aristarán, came out months ago, but I've been poking at government data recently and came back to this useful piece of free software to get the data tables out of countless free-floating PDF files.

    If you've ever tried to do anything with data provided to you in PDFs, you know how painful this is — you can't easily copy-and-paste rows of data out of PDF files. Tabula allows you to extract that data in CSV format, through a simple interface.

    It's not the fastest software in the world, but it really is simple to use and it sure beats manual entry. You just load a PDF file into Tabula, which runs on your computer, highlight the table to extract, and the program does the rest. Save as a CSV and do what you want with it.

    Download Tabula here. Find out a little more about it on Source.

  • Regional macrobrews

    April 7, 2014  |  Mapping

    Beer tweeting

    FloatingSheep pointed their Twitter geography towards beer (and wine).

    From Sam Adams in New England to Yuengling in Pennsylvania to Grain Belt and Schlitz in the upper Midwest, these beers are quite clearly associated with particular places. Other beers, like Hudepohl and Goose Island are interesting in that they stretch out from their places of origin -- Cincinnati and Chicago, respectively -- to encompass a much broader region where there tend to be fewer regionally-specific competitors, at least historically. On the other hand, beers like Lone Star, Corona and Dos Equis tend to have significant overlap in their regional preferences, with all three having some level of dominance along the US-Mexico border region, but with major competition between these brands in both Arizona and Texas.

    This of course excludes the increased appreciation for craft beer, as there isn't enough data for significant microbrewery results.

  • Fox News bar chart gets it wrong

    April 4, 2014  |  Mistaken Data

    Fox News bar chart

    Because Fox News. See also this, this, and this. [Thanks, Meron]

  • Big data, same statistical challenges

    April 4, 2014  |  Statistics

    Tim Harford for Financial Times on big data and how the same problems for small data still apply:

    The multiple-comparisons problem arises when a researcher looks at many possible patterns. Consider a randomised trial in which vitamins are given to some primary schoolchildren and placebos are given to others. Do the vitamins work? That all depends on what we mean by “work”. The researchers could look at the children’s height, weight, prevalence of tooth decay, classroom behaviour, test scores, even (after waiting) prison record or earnings at the age of 25. Then there are combinations to check: do the vitamins have an effect on the poorer kids, the richer kids, the boys, the girls? Test enough different correlations and fluke results will drown out the real discoveries.

    You're usually in for a fluffy article about drowning and social media when 'big data' is in the title. This one is worth the full read.

  • Open access to 20,000 maps from NYPL

    April 3, 2014  |  Mapping

    Maps from NYPL

    The New York Public Library announced open access to 20,000 maps, making them free to download and use.

    The Lionel Pincus & Princess Firyal Map Division is very proud to announce the release of more than 20,000 cartographic works as high resolution downloads. We believe these maps have no known US copyright restrictions.* To the extent that some jurisdictions grant NYPL an additional copyright in the digital reproductions of these maps, NYPL is distributing these images under a Creative Commons CC0 1.0 Universal Public Domain Dedication. The maps can be viewed through the New York Public Library's Digital Collections page, and downloaded (!), through the Map Warper

    Begin your journey.

  • Planetary layer cake

    April 2, 2014  |  Mapping

    Planetary layer cake

    From Cakecrumbs, a product that helps you learn while you eat: planetary layer cakes. The graduate student slash baker hobbyist's sister asked if she could make one, and at first she thought it couldn't be done. But then she thought more about it.

    I spent the rest of the afternoon thinking about it. I don’t admit defeat. Ever. But especially not with cake. Nothing is impossible is pretty much my baking motto, so to say this cake was impossible left me feeling weird. There had to be a way. A way that didn't involve carving or crumbing the cake. I kept mulling it over until I had a breakthrough.

    See how it was done.

  • Bike share data in New York, animated

    April 1, 2014  |  Data Sources

    Citi Bike, also known as NYC Bike Share, is releasing monthly data dumps for station check-outs and check-ins, which gives you a sense of where and when people move about the city. Jeff Ferzoco, Sarah Kaufman, and Juan Francisco Saldarriaga mapped 24 hours of activity in the video below.

    [Thanks, Jeff]

  • Dead links on the Million Dollar Homepage

    April 1, 2014  |  Statistics

    Million dollar homepage

    Remember the Million Dollar Homepage from 2005? It sold ad space to anyone who was interested for one dollar per pixel, and there were one million pixels available. All spots were filled, and it gave a burst of bunch of other million dollar homepages that turned out to be zero dollar homepages.

    David Yanofsky for Quartz returned to the homepage to look at link rot. 22 percent of links on the homepage are dead.

  • Exponential water tank

    March 31, 2014  |  Infographics

    Exponential water tank

    Hibai Unzueta, based on a paper by Albert Bartlett, demonstrates exponential growth with a simple animation. It depicts a man standing in a tank with finite capacity and water rising slowly, but at an exponential rate.

    Our brains are wired to predict future behaviour based on past behaviour (see here). But what happens when something growths exponentially? For a long time, the numbers are so little in relation to the scale that we hardly see the changes. But even at moderate growth rates exponential functions reach a point where the numbers grow too fast. Once we confirm that our predictions about the future have failed, very little time to react may be left.

    All looks safe at first, because the water rises so slowly, but it seems to rise all of a sudden. Oh, the suspense. What will happen to cartoon pixel man?

  • Centuries of European border changes

    March 28, 2014  |  Mapping

    The Centennia Historical Atlas is a program that shows you border changes in Europe and the Middle East, from the 11th century to the present. It's meant as an educational tool. The video below is the animated map from the program set to climactic music from the movie Inception.

    Now contrast that to the original promotional video for Centennia. I'm amused. [via @sogrady]

  • Smoking rates and income

    March 27, 2014  |  Mapping

    Smoking rates

    Based on a study on smoking prevalence from 1996 to 2012, a map by The New York Times shows the results. Smoking rates among men and women have declined overall over the years, but there are still relatively high rates in many areas of the country, which appears to correlate with income. Lower income tends towards higher smoking rates.

    That would explain why the map above looks similar to a county-level map for median household income, which probably interacts with life spans by county somehow.

  • Reconstructing Google Streetview as a point cloud

    March 26, 2014  |  Mapping

    Patricio Gonzalez Vivo, an MFA Design & Technology student, scraped depth from Google Streetview and then reconstructed it in openFrameworks. The result is Point Cloud City. See it in action in the video below.

    Dreamlike.

    Now I'm curious what else can be gleaned from this data, because this essentially means you could get really detailed data about the makeup of places, down to the window of a building. Although I don't imagine Google will let this stay so accessible for long. [Thanks, @pixelbeat]

  • Human heartbeat

    March 26, 2014  |  Data Art

    Human heart beat

    Jen Lowe tracks her heart rate with a Basis watch, and she's showing the last 24 hours of that data in One Human Heartbeat.

    Basis doesn't provide an open API, so I access the data using a variation of this code. The heartrate you see is from 24 hours ago. This is because the data can only be accessed via usb connection. Twice a day I connect the watch and upload my latest heartrates to the database. I've been doing this for 33 days now.

    It's March 25, 2014, and statistics say I have about 16452 days left.

    On the surface, it's just a pulsating light on a screen, but somehow it feels like more than that. The countdown aspect makes me uneasy, as if I were watching a ticker on someone's life, or my own even. I want to keep watching though, because it continues to pulsate. It's hopeful.

  • How to make density maps

    How to Make Smoothed Density Maps in R

    Too many points to plot often means obscured patterns in the clutter. Density maps offer a smooth alternative.
  • Level of road grid

    March 25, 2014  |  Mapping

    Road orientation

    Seth Kadish looked at the road network of several major counties and estimated the directions the streets run. The result is a set of charts that shows which cities use a grid system and those that don't.

    If you're like me, and you use the Sun to navigate, you probably appreciate cities with gridded street plans that are oriented in the cardinal directions. If you know that your destination is due west, even if you hit a dead end or two, you'll be able to get there. However, not all urban planners settled on such a simple layout for road networks. For some developers, topography or water may have gotten in the way. Others may not have appreciated the efficiency of the grid. This visualization assesses those road networks by comparing the relative degree to which they are gridded.

    Whoa, Charlotte.

    Since the original, Kadish has added more counties and a handful of international cities.

  • Graph TV shows ratings by episode

    March 24, 2014  |  Statistical Visualization

    Ratings for The Office

    Kevin Wu made a straightforward interactive that lets you see IMDB television ratings over time, per episode and by season.
    Continue Reading

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