2813 search results for "gis"

A slightly different introduction to R, part I

January 19, 2013
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A slightly different introduction to R, part I

Note in Swedish: Jag hoppas läsaren ursäktar att jag skriver på engelska då och då. This will be a brief introduction to using the statistics software R for biologists who want to do some of their data analysis in R. There are plenty of introductions to R (see here and here, for example; these are

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Using Rcpp to access the C API of xts

January 19, 2013
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Using Rcpp to access the C API of xts

The xts package by Jeff Ryan and Josh Ulrich is an immensely powerful tool that is widely used for timeseries work with R. Recently, the question about how to use it from Rcpp came up on StackOverflow and in a thread on the rcpp-devel list. In fact, xts has had an exposed API since 2008, but it...

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Using Rcpp to access the C API of xts

January 19, 2013
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Using Rcpp to access the C API of xts

The xts package by Jeff Ryan and Josh Ulrich is an immensely powerful tool that is widely used for timeseries work with R. Recently, the question about how to use it from Rcpp came up on StackOverflow and in a thread on the rcpp-devel list. In fact, xts has had an exposed API since 2008, but it...

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Safely Loading Packages in R

January 18, 2013
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Using R snippets written by other developers can be unendingly maddening.  There are a variety of reasons for this, most of which boil down to a simple issue: most code is written such that a system must be configured in … Continue reading →

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Dynamically annotate graphs with Shiny

January 18, 2013
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Dynamically annotate graphs with Shiny

Below I present a simple way to automatically annotate plots through Shiny It occurred to me that labeling plots should be really easy to do with R-studio's swanky 'Shiny' add on. To test this I gathered some time series data from Wikipedia, added opt...

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Power Calculations – relationship between test power, effect size and sample size

January 17, 2013
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Power Calculations – relationship between test power, effect size and sample size

I was interested in modeling the relationship between the power and sample size, while holding the significance level constant (p = 0.05) , for the common two-sample t-Test. Luckily R has great support for power analysis and I found the function I was looking for in the package pwr. To calculate the power for the two-sample T-test

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Calculating a Gini Coefficients for a Number of Locales at Once in R

January 17, 2013
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Calculating a Gini Coefficients for a Number of Locales at Once in R

The Gini coefficient is a measure of the inequality of a distribution, most commonly used to compare inequality in income or wealth among countries.Let's first generate some random data to analyze. You can download my random data or use the code below ...

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Maize trade Part I: Generate the network diagram

January 17, 2013
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Maize trade Part I: Generate the network diagram

It has been several month since my last post, partially due to the fact that my laptop was lost and several deadlines was approaching. Fortunately I will be returning to Taiwan and get a new laptop within a week, and will be updating regularly...

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Steve Culman on the `plyr` Package

January 17, 2013
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At Davis R Users’ Group yesteray, Steve Culman gave us an introduction to the plyr package and how to use it to manipulate data. Here’s his presentation, and the accompanying demonstration script: Steve’s talk is based on this paper by Hadley Wickham in the Journal of Statistical Software. A lot of useful related...

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Plotting Odds Ratios (aka a forrestplot) with ggplot2 –

January 17, 2013
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Plotting Odds Ratios (aka a forrestplot) with ggplot2 –

Hi, if you like me work in medical research, you have to plot the results of multiple logistic regressions every once in a while. As I have not yet found a great solution to make these plots I have put together the following short skript. Do not expect too much, it’s more of a reminder

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