Extracting Raster Values from Points in R and GRASS

July 26, 2010
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A common task in GIS analysis is to extract the value of a remotely sensed environmental variable at a point location. For instance we may wish to extract the elevation of a field plot from a digital elevation model. The elevation data is a raster (i.e. grid) and the plots are a point shapefile (or a simple text file of X,...

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Richard Stallman talk+Q&A at the useR! 2010 conference (audio files attached)

July 26, 2010
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The audio files of the full talk by Richard Stallman are attached to the end of this post. —————– Videos of all the invited talks of the useR! 2010 conference can be viewed on the R User Group blog —————– Last week I had the honor of attending the talk given by Richard Stallman, the last keynote speaker on...

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Using SAS for Data Management, Statistical Analysis, and Graphics

July 26, 2010
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Using SAS for Data Management, Statistical Analysis, and Graphics

Our newest book, Using SAS for Data Management, Statistical Analysis and Graphics, will soon be shipping from Amazon, CRC Press, and other fine retailers. The book complements our SAS and R book, particularly for users less interested in R. It presen...

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New R User Group in Melbourne

July 26, 2010
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Data mining analyst Yuval Marom has just started a new user group for users of R in Melbourne (the one in Australia). He says: The group is open to people with all levels of experience with R, including complete beginners and complete experts, and people from all industries - private, government, and academic. The main purpose of the group...

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R Plotting tips

July 26, 2010
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Yes...I haven't been updating the blog for a very long while...But I'm really busy with many things right know.... Our paper for the "Cultural Evolution in Spatially Structured Populations" have been accepted so we are currently working on that, and I ...

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R Plotting tips

July 26, 2010
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Yes...I haven't been updating the blog for a very long while...But I'm really busy with many things right know.... Our paper for the "Cultural Evolution in Spatially Structured Populations" have been accepted so we are currently working on that, and I ...

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Circle packing with R

July 26, 2010
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Circle packing with R

To visualize the results of a simulation model of woodland trees within R, I needed an algorithm that could arrange a large number of circles within a rectangle such that no two circles overlapped by more than a specified amount. A colleague had approached this problem earlier by sorting the circles in order of descending size, then randomly dropping...

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Circle packing with R

July 26, 2010
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Circle packing with R

To visualize the results of a simulation model of woodland trees within R, I needed an algorithm that could arrange a large number of circles within a rectangle such that no two circles overlapped by more than a specified amount. A colleague had approa...

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Asher’s enigma

July 25, 2010
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Asher’s enigma

On his Probability and statistics blog, Matt Asher put a funny question (with my rephrasing): Take a unit square. Now pick two spots at random along the perimeter, uniformly. For each of these two locations, pick another random point from one of the three other sides of the square and draw the segment. What is

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R Chart

July 24, 2010
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R Chart

Been meaning to write this for awhile...An R-Chart is a statistical quality assurance tool used to determine if a process is stable (and predictable).  It is intended to maintain and improve the quality of a process (a more formal definition is av...

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useR 2010 at NIST in Gaithersburg

July 24, 2010
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This past week, the annual R user conference useR! 2010 took place at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD (which is a tad northwest of Washington, DC). Kate Mullen and her team of local organizers did a truly...

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useR 2010 at NIST in Gaithersburg

July 24, 2010
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This past week, the annual R user conference useR! 2010 took place at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD (which is a tad northwest of Washington, DC). Kate Mullen and her team of local organizers did a truly t...

Read more »

useR 2010 at NIST in Gaithersburg

July 24, 2010
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This past week, the annual R user conference useR! 2010 took place at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD (which is a tad northwest of Washington, DC). Kate Mullen and her team of local organizers did a truly...

Read more »

Local R User Group Panel from useR! 2010 (Video)

July 24, 2010
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As I mentioned last week, I will be hosting videos of several of the keynote speakers from this year’s useR! 2010 conference at the video Rchive. As it happens, the first video I was able to upload was the panel discussion we held on starting local R user groups. I have uploaded the video,

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useR! 2010 – Local R User Group Panel

July 24, 2010
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Panel discussion about forming local R user groups from useR! 2010. Panelists include, Jim Porzak (San Francisco Bay Area), David Smith (REvolution Analytics), John C. Nash (Ottawa, Canada), Drew Conway (New York City), Szilard Pafka (Los Angeles), M...

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How to calculate with dates and hours in R

July 24, 2010
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How to calculate with dates and hours in R

A while ago I was asked whether calculating with datums and hours is possible in R. Especially, if you added an hours to 23:45 (say Jan 1, 2010) , would R know to jump to the next day – 00:45 (jan 2, 2010)? The answer is yes. Our only job is to tell R in

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useR! 2010 done and dusted

July 23, 2010
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useR! 2010 done and dusted

:

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Installing rgdal on Mac OS X

July 23, 2010
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The rgdal package contains bindings from R to the GDAL (Geospatial Data Abstraction Library) as well as the PROJ library. It is a dependency for numerous spatial statistics packages. Note that the binaries on the rgdal homepage are outdated — the most up-to-date version of the rgdal package can be found on CRAN. Unsurprisingly, rgdal

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Hello world!

July 23, 2010
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Throughout the course of my research, I come across a lot of obstacles and nuisances that are either undocumented or documented poorly.  Therefore, I decided to throw up this blog as a repository of sorts to store all of these little tidbits of information with the hope that it will save somebody somewhere a few minutes of

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Thoroughly Unusual Itches

July 23, 2010
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Thoroughly Unusual Itches

I have found myself over the years in a rather awkward situation.  I work in old-school, bricks and mortar industry IT shops for the most part.  However, I love many open source projects and identify with many of the values of start up cultur...

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The counterfactual GPS!

July 23, 2010
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The counterfactual GPS!

WHAT IF YOUR GPS TOLD YOU WHAT WOULD HAVE HAPPENED IF YOU HAD TAKEN THE OTHER ROUTE? Not long ago, your Decision Science News editor was planning a trip to a book group meeting along with another member. The monthly book group takes place in Cove Neck Long Island, about an hour East of Manhattan.

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Why building R packages is good for you

July 23, 2010
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Basically every function you use in R is part of a package (often the base or stats one). Most of the advances routines, such as the differential equations solvers in simecol are brought to R in the form of Fortran (…)Read the rest of this entry »

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Turning your data into a 3d chart

July 23, 2010
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Turning your data into a 3d chart

Some charts are to help you analyse data. Some charts are to wow people. 3d charts are often the latter, but occasionally the former. In this post, we’ll look at how to turn your data into a 3d chart. Let’s use the data from this previous post. Use the code which turns the .csv spreadsheet

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Plaudits for R

July 23, 2010
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I just discovered that R core member Paul Murrell has been maintain a list of plaudits for R: newspaper articles, book reviews, remarks on mailing lists and blogs, and even gratitudes from individual R users. He's collected dozens of entries since 2001 -- great materials here if you ever need more evidence of the awesomeness of R. Paul Murrell:...

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Building an R package (under Windows) without C, C++ or FORTRAN code

July 23, 2010
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Building an R package (under Windows) without C, C++ or FORTRAN code

Why build and R package? It basically boils down to be able to brag at your local pub that a new version of YOUR package is on CRAN as of 7 p.m. CET. But seriously, if you’ve produced some function that other people might benefit (or have ordered them) from using them, like your boss,

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Creating a Presentation with LaTeX Beamer – Equations and tikz

July 23, 2010
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Creating a Presentation with LaTeX Beamer – Equations and tikz

Many presentations created using LaTeX beamer included mathematical equations and these can be easily included in a presentation and in this post we will consider using the tikz package to add various interesting elements to equations, such as lines between text on a slide and part of an equation. Fast Tube by Casper The examples on this

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UseR! 2010 day 1

July 22, 2010
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Just a couple of quick notes about the first day of talks at useR! 2010. It's been a jam-packed schedule -- so many good talks to see and people to meet, I just wish I had more time for it all! One stand-out for me so far has been Frank Harrell's keynote lecture Information Allergy, on the dangers of...

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Quick scatterplot with associated histograms

July 22, 2010
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Quick scatterplot with associated histograms

R can produce some beautiful graphics, and there are some excellent packages, such as lattice and ggplot2 to represent data in original ways.  But sometimes, all you want to do is explore the realtionship between pairs of variables with the minimum of fuss. In this post we’ll use the data which we imported in the

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Update to ‘Basic R’ eBook

July 22, 2010
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(This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: Rmetrics blogs. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web...

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