2642 search results for "gis"

Rolling means (and other functions) with zoo

December 2, 2012
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Rolling means (and other functions) with zoo

The zoo package is designed for use with (potentially irregular) time series data. It is widely used for any number of applications, but among its most frequently useful functions are the roll* functions, such as rollmean, rollmedian, rollmax, rollapp...

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Using XML to grab tables from the web

December 1, 2012
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Using XML to grab tables from the web

We’re going to try, this December, to bring you an “Advent CalendaR,” for each of the 24 days leading up to Christmas. Each day, our hope is to unwrap a useful R package to show you a useful or interesting function inside! Today&#821...

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Trading with Support Vector Machines (SVM)

November 30, 2012
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Trading with Support Vector Machines (SVM)

Finally all the stars have aligned and I can confidently devote some time for back-testing of new trading systems, and Support Vector Machines (SVM) are the new “toy” which is going to keep me busy for a while. SVMs are a well-known tool from the area of supervised Machine Learning, and they are used both

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Lauren Yamane on Matrix Population Models in R

November 30, 2012
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Lauren Yamane on Matrix Population Models in R

Last week in Davis R Users’ Group, Lauren Yamane showed us how she created and analyzed a stochastic age-structured population in R. Her examples are below. Her original scripts can be found as *.Rmd files here A note to UC Davis students: This topic and others will be covered by Marissa Baskett and Sebastian Schreiber in...

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Finding a bright object

November 30, 2012
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Finding a bright object

Finally, to return to the challenge I laid out in the first of this series on image manipulation in R: can we do anything as cool in R as can be done in Mathematica? Like, for example, this illustration of how to search images of the surface of Mars...

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Shiny is the new Cool

November 29, 2012
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Shiny is the new Cool

Several of you will probably have tried out the new Shiny package brought to the table by the RStudio guys This is just what I have been looking for and to my mind could provide a quantum leap in the use of R. There have been other packages addressing the need for web user interactivity

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Sorting Within Lattice Graphics in R

November 29, 2012
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Sorting Within Lattice Graphics in R

DefaultBy default, lattice sorts the observations by the axis values, starting at the bottom left.For example,library(lattice)colors = c("#1B9E77", "#D95F02", "#7570B3")dotplot(rownames(mtcars) ~ mpg, data = mtcars, col = colors, pch = 1)produc...

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Picking Lotto Numbers

November 28, 2012
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There's not a lot you can do to increase your odds of winning the lottery tonight. With the PowerBall at $500 million though, a lot of otherwise rational folks might be tempted into playing. For those of you newly tempted, it is important to remember a...

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Images as Voronoi tesselations

November 28, 2012
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Images as Voronoi tesselations

This is probably the coolest-looking thing I’ve figured out how to do with raster images in R. Similar to (although not quite as impressive as) these images by Jeff Clark, I alter the simple k-means approach described in the previous post to...

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Why [Not] Simulate?

November 27, 2012
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Why [Not] Simulate?

Since we are in the “big data” Era, which means that a massive amount of data are made daily available by governments, institutions, and ordinary people like you and me—the importance of simulate data for “frequentists”, like myself, seems to fade. After all, once we have access to “real data”, why bother with non-real data,

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