06/30/15

Physical representation of a record breaking month of rain

AHPSMaypptdiffAccording to NOAA, this past May was the wettest month on record for the the US. The distribution of rain was not uniform. Parts of the central US received 2 to 3 times as much rain as usual while precipitation on the most of the East and West coasts was below average. Continue reading

07/24/14

The challenge of using area to communicate values in visualizations

Bubble charts are a popular way to present quantitative data. Often the area of the circles in the bubble chart are used to encode the value of a parameter. The larger the value, the greater the area, the bigger the circle. This makes intuitive sense and can be quite effective for rough comparisons. However, it is important to understand that we are not very good at estimating area and  these representations distorts the data because we are not very good at estimating area.
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09/22/13

Dynamic, Stacked Timeline Visulaization

ACF Basin

Apalachicola-Chattahoochee-Flint River Basin

The Apalachicola-Chattahoochee-Flint River water basin (ACF Basin) extends across three states: Georgia, Alabama and Florida. The watershed is the focus of a long running water use dispute between stakeholders in these three states. This conflict is covered in the book “Water Diplomacy: A Negotiated Approach to Managing Complex Water Networks” by Shafiqul Islam and Lawrence E. Susskind. An early figure on the book (figure 2.1, page 11) uses a stacked timeline to show how the water use issues in the ACF Basin became more complex as the population in the region grew and the number of interested parties increased over time.
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06/10/13

Simultaneous brightness contrast illusion

Our eyes give us a very subjective view of the world. This subjectivity leaves us susceptible to a variety of optical illusions. The fact that we are not very good at estimating the absolute brightness of a region, but have a strong ability to detect differences between neighboring regions causes simultaneous brightness contrast illusions. This type of illusion makes the perceived brightness of any region in a complex image vary depending on the brightness of the region’s immediate surroundings.

The illustration below shows how our perception of a solid grey square is influenced by the background. The two squares below are the same shade of grey, but the lighter background behind the square on the left makes that square appear darker than the one on the right.
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09/17/12

Aquaculture production of exotic species by country

Blue Frontiers: Managing the environmental costs of aquaculture (Hall et al., 2011), from the World Fish Center is an incredibly data rich report. It is a must read for anyone interesting in the promise of aquaculture and the challenges involved in moving towards more sustainable practices.
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