3750 search results for "gis"

Creating a matrix from a long data.frame

October 1, 2013
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There can never be too many examples for transforming data with R. So, here is another example of reshaping a data.frame into a matrix.Here I have a data frame that shows incremental claim payments over time for different loss occurrence (origin) years...

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Regression on variables, or on categories?

September 30, 2013
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I admit it, the title sounds weird. The problem I want to address this evening is related to the use of the stepwise procedure on a regression model, and to discuss the use of categorical variables (and possible misinterpreations). Consider the following dataset > db = read.table("http://freakonometrics.free.fr/db2.txt",header=TRUE,sep=";") First, let us change the reference in our categorical variable  (just to...

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Which is the best "Flyover" state?

September 30, 2013
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Which is the best "Flyover" state?

If you were to hop into your personal aircraft, and plotted a straight line course taking off in one state and landing in the SAME state, how many other states might you fly over? On other words, what's the best state for "flyovers" of other states? Todd Schnieder from the Rapgenius engineering team answered that question using the R...

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An R function to download shapefiles

September 30, 2013
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An R function to download shapefiles

This post is a follow up from my latest Things I Forget post on reading in shapefiles.  That post assumed that you already had access to all the relevant files (e.g. .shp, .shx, .prj, .dbf, etc.).  A task that I routinely need to do is locate shapefiles on a website, grab those files, and read

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ROC curves and classification

September 30, 2013
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ROC curves and classification

To get back to a question asked after the last course (still on non-life insurance), I will spend some time to discuss ROC curve construction, and interpretation. Consider the dataset we’ve been using last week, > db = read.table("http://freakonometrics.free.fr/db.txt",header=TRUE,sep=";") > attach(db) The first step is to get a model. For instance, a logistic regression, where some factors were merged...

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eoda’s R-academy celebrates its third anniversary and is extending the extensive training program for R

September 30, 2013
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The free statistical programming language R becomes more and more popular, even in German speaking areas. This happens for various reasons. Besides from its performance, its quality and its open source character, R scores with its various possibilities for integration. Beyond that R offers a multitude of possibilities in the field of multivariate analysis methods.

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New version of lme4

September 30, 2013
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If you haven't realized it yet, a new version of lme4 (version 1.0-4) was released recently (Sept. 21). For an end-user like me, there were not many changes, but there were a few:No more using the @ operator. After a very helpful email exchange with Be...

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Making of elliplot package

September 28, 2013
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Making of elliplot package

The elliplot package is my first package for R.  So I want to write down details of making that, both for myself and for people following. original source The ellipseplot … Continue reading →

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Forecasting Using R: A new online course from Rob Hyndman

September 27, 2013
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Statistical forecasting is a critical component of every modern business, and Rob J Hyndman, Professor of Statistics at Monash University, is an expert in the field. He's the co-author of several books on forecasting, including Forecasting: Principles and Practice, a free on-line book that provides a comprehensive introduction to forecasting methods. You can implement all of the methods in...

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Things I Forget: Reading a Shapefile in R with readOGR

September 27, 2013
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Things I Forget: Reading a Shapefile in R with readOGR

One of the more common ways that I read vector data into R is via shapefiles.  I tend to use these partly becuase of my own sordid past with Arc/INFO, ArcView and ArcGIS and partly due to their ubiquity.  In any event I have found the R package, rgdal, indespensible for this.  One of the

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