Monthly Archives: October 2012

From holey polygons to convex hulls

October 11, 2012
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From holey polygons to convex hulls

I only rarely have the occasion to need the convex hull of a set of points, but I love chull(), so I’d like to share an example of how to use it. This Gist also offers a pretty straightforward application of the Split-Apply-Combine strategy (see...

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Curved arrows in R

October 10, 2012
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Curved arrows in R

I briefly investigated how to draw curved arrows in R. Here’s a small piece of the figure that I ultimately created: A google search for “curved arrows in R” revealed three options: curvedarrow in the diagram package The internal function igraph.Arrows within the igraph package (mentioned by Gabor Csardi in R help) Using xspline for

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Know Your Dataset: Specifying colClasses to load up an ffdf

October 10, 2012
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Know Your Dataset: Specifying colClasses to load up an ffdf

When I finally figured out how to successfully use the ff package to load data into R, I was apparently working with relatively pain free data to load up through read.csv.ffdf (see my previous post).  Just this past Sunday, I … Continue reading →

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analyze the current population survey (cps) annual social and economic supplement (asec) with r

October 10, 2012
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the annual march cps-asec has been supplying the statistics for the census bureau's report on income, poverty, and health insurance coverage since 1948.  wow.  the us census bureau and the bureau of labor statistics (bls) tag-team on this one...

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R amongst most popular languages, according to GitHub/StackOverflow data

October 10, 2012
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R amongst most popular languages, according to GitHub/StackOverflow data

Data Scientist Drew Conway tackles the problem of deciding which programming languages are the most popular in an interesting way: by comparing the number of projects tagged in GitHub with each language, and the number of questions in StackOverflow about the language. The former is a measure of how often a language is used (though, mainly for open source...

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2012-6 Working with the gridSVG Coordinate System

October 10, 2012
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The gridSVG package exports grid images to an SVG format for viewing on the web. This article describes new features in gridSVG that allow grid coordinate system information to be exported along with the image. This allows the SVG image … Continue reading →

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What lens should I buy next ?; Analysing and graphing a Digikam database using R

October 10, 2012
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I use the Open Source photo management Software Digikam (along with other tools such as Gimp and DarkTable).  I obviously need very little encouragement to combine my geeky hobbies, so I quickly tried to interrogate Digikam with R, which is easy, ...

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Summarizing Circular Data in R: Aspect Angle

October 10, 2012
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Summarizing Circular Data in R: Aspect Angle

The orientation of terrain surface (aspect) can have dramatic effects on landscape-scale variation in soil temperature and moisture. Summarizing aspect angle is complicated by the fact that sampled values are measured on a circular scale. The circular ...

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Simple marimekko/mosaic plots

October 10, 2012
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Simple marimekko/mosaic plots

I don’t really care for the name “marimekko” or “mosaic,” but I do like this type of plot as a means of illustrating proportions in nested categorical data, or as an alternative to the parallel time series plots discussed...

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S&P 500 sector strengths

October 10, 2012
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S&P 500 sector strengths

Which sectors are coherent, and which aren’t? Previously The post “S&P 500 correlations up to date” looked at rolling mean correlations among stocks.  In particular it looked at rolling mean correlations of stocks within sectors. Of importance to this post is that the sectors used are taken from Wikipedia. Relative correlations The thought is that … Continue reading...

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