3174 search results for "gis"

Visualising Crime Hotspots in England and Wales using {ggmap}

June 24, 2013
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Visualising Crime Hotspots in England and Wales using {ggmap}

Two weeks ago, I was looking for ways to make pretty maps for my own research project. A quick search led me to some very informative blog posts by Kim Gilbert, David Smith and Max Marchi. Eventually, I Google'd the excellent crime weather map exa...

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My Stat Bytes talk, with slides and code

June 24, 2013
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On Thursday of last week I gave a short informal talk to Stat Bytes, the CMU Statistics department‘s twice a month computing seminar. Quick tricks for faster R code: Profiling to Parallelism Abstract: I will present a grab bag of … Continue reading →

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Principal Components Analysis Shiny App

June 23, 2013
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Principal Components Analysis Shiny App

I’ve recently started experimenting with making Shiny apps, and today I wanted to make a basic app for calculating and visualizing principal components analysis (PCA). Here is the basic interface I came up with. Test drive the app for yourself using the code below or  check out the the R code HERE. Above is an example of the

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Time Is on My Side – A Small Example for Text Analytics on a Stream

June 23, 2013
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Time Is on My Side – A Small Example for Text Analytics on a Stream

Introduction and Background While my last posting was about recommendation in the context of Location Based Social Networks there are also other interesting topics regarding the analysis of unstructured data. The most established one is probably Text Analytics/Mining focusing on all sorts of text data.For me, coming from spatial analysis, these topic is relatively new but I couldn’t help noticing...

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Got Bootstrap?

June 23, 2013
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Got Bootstrap?

This week I read the book by Michael Chernick and Robert LaBudde, An Introduction to Bootstrap Methods with Applications to R. It’s an interesting oeuvre for useRs of all stripes. I strongly recommend check it out. The book brings lots of examples of bootstrapping applications, such as standard errors, confidence intervals, hypothesis testing, and even

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GRNN and PNN

June 23, 2013
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GRNN and PNN

From the technical prospective, people usually would choose GRNN (general regression neural network) to do the function approximation for the continuous response variable and use PNN (probabilistic neural network) for pattern recognition / classification problems with categorical outcomes. However, from the practical standpoint, it is often not necessary to draw a fine line between GRNN

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Prototyping A General Regression Neural Network with SAS

June 22, 2013
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Prototyping A General Regression Neural Network with SAS

Last time when I read the paper “A General Regression Neural Network” by Donald Specht, it was exactly 10 years ago when I was in the graduate school. After reading again this week, I decided to code it out with SAS macros and make this excellent idea available for the SAS community. The prototype of

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Advanced Graphics I

June 22, 2013
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Advanced Graphics I

Polygon is a such handy function in R for drawing beautiful charts where we can select regions (polygons) of the surface. It’s quite useful for indicating confidence regions of parameters, predictions for time-series, or areas under distributions:

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Calling C++ from R using Rcpp

June 22, 2013
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Why call C/C++ from R? I really like programming in R. The fact that it is open source immediately wins my favour over Matlab. It can, however, be quite slow especially if you “speak” R with a strong C/C++ accent. This sluggishness, especially when writing unavoidable for loops, has led me to consider other programming The post Calling...

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Not only CRAN downloads and Shiny … but also .. rCharts

June 21, 2013
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Not only CRAN downloads and Shiny … but also .. rCharts

I have been meaning for some time to get stuck into the rCharts package which provides an interface to many Javascript graphic libraries. These offer rich charting capabilities with interactivity and a great deal of customization. As regular readers will know, I am also interested in improved publicity for CRAN packages, although the Shiny app

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