From the Vaults: Maps are Just Another Element

For the Grammar of Graphics language-based approach to visualization, and therefore in the RAVE visualization system, maps are simply another element that can be used within the grammatical formulation.

Although most people consider a map a very different entity from a bar chart, all that really differs between a bar chart and a map of areas like the one included here is that instead of representing a row of data by a bar, we use a polygon (or set of polygons) on a map. Otherwise their properties ought to be the same — we can apply color, patterns, labels, transparency. We can set a summary statistic when there are multiple values for each polygon to reflect min, max, mean, median, range, or any of the regular sets of items. We can flip, transpose and panel the charts. Essentially, from the grammatical point of view, if you can do it to a bar chart, you can do it to a map. The only limitation is that whereas the sizes of the bars can be set or determined by data, the map polygons cannot, so setting sizes on the map polygons has no effect.

US Chorlopleth

Orthogonality is also important — so we can say we want a point element instead of a polygon, as in the above where we’ve added a second element to a RAVE US Map conveying different data as well as being a good place to put labels

About workingvis

Visualization is the science of making pictures out of data so that they inform the viewer and allow them to understand the data and take action based on what can be seen. I create new methods of interacting with data using a computer interface and try to understand what tools help people model their data and find patterns and unusual features. I have a background in statistics and statistical graphics, and work with computer scientists as well as statisticians. My particular interests include research into: * Fundamental methods for interaction with data views * Statistical methods to improve or motivate visualization design * The interface between statistical models and statistical graphics * Visualization of large weighted graphs * Ways to use knowledge discovery techniques with visualization Specialties:visualization, research, statistics, statistical modeling, graphics, information visualization, agile development, spatial statistics, time series

Posted on 2013/04/26, in Domain-Specific and tagged , , , , , . Bookmark the permalink. Leave a comment.

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