Monthly Archives: June 2013

PivotalR Improves the Scalability and Performance of In-Database Analytics

June 18, 2013
By
PivotalR Improves the Scalability and Performance of In-Database Analytics

One of the greatest challenges while working with big datasets concerns the need to move information out of storage for analysis. To this end, the recent announcement of PivotalR 0.1 extends Pivotal HD's capabilities, allowing users of the statistical programming language R to perform in-database analytics without leaving the command line.

Read more »

R GIS: Terrain Analysis for Polygons as Simple as it Gets!

June 18, 2013
By
R GIS: Terrain Analysis for Polygons as Simple as it Gets!

library(rgdal)library(raster)alt gadm gadm_sub plot(alt)plot(gadm_sub, add=T)asp slo > extract(slo, gadm_sub, fun = mean, na.rm = T, small = T, df = T) ID slope1 1 9.9590532 2 1.0474433 3 7.4561654 4 1.6737865 5 11.946553> extract(asp, gadm_sub, fun = mean, na.rm = T, small...

Read more »

The Green Number Effect

June 18, 2013
By
The Green Number Effect

Following up on a suggestion from my previous post, here are the statistics for medal count versus age. Every point on the plot is the number (see colour legend on right) of athletes who have achieved a given number of medals by a particular age. There is clear evidence of a Green Number Effect: many

Read more »

Quickly read Excel worksheets into R (Windows only…sorry)

June 18, 2013
By

I suppose most companies use the Microsoft Office suite of programs, and my office is no exception. It easy to import data from an API or a database into R, but importing data from an Excel workbook is a different story. There are a few R packages for reading Excel files, but I’ve had problems

Read more »

Job opening! Come work with us!

June 18, 2013
By

Postdoctoral position in statistical modeling of social networks A full-time postdoctoral position is available beginning Fall 2014 in the research group of Tian Zheng and Andrew Gelman working on statistical analysis and modeling of social network data, in close cooperation with our experimental collaborators. Four key papers of this project so far are: http://www.stat.columbia.edu/~gelman/research/published/overdisp_final.pdf http://nersp.osg.ufl.edu/~ufruss/documents/mccormick_salganik_zheng10.pdf The post Job...

Read more »

Use R to Bulk-Download Digital Elevation Data with 1" Resolution

June 18, 2013
By

Here's a little r-script to convenientely download high quality digital elevation data, i.e. for the Alps, from HERE:require(XML)dir.create("D:/GIS_DataBase/DEM/")setwd("D:/GIS_DataBase/DEM/")doc urls names for (i in 1:length(urls)) download.file(urls, names) # unzip all files in dir and delete them afterwardssapply(list.files(pattern = "*.zip"), unzip)unlink(list.files(pattern = "*.zip"))p.s.: Also check raster::getData which pulls SRTM data at 90m resolution for a location / region!

Read more »

Evaluating Optimization Algorithms in MATLAB, Python, and R

June 18, 2013
By
Evaluating Optimization Algorithms in MATLAB, Python, and R

As those of you who read my last post know, I’m at the NIMBioS-CAMBAM workshop on linking mathematical models to biological data here at UT Knoxville. Day 1 (today) was on parameter estimation and model identifiability. Specifically, we (quickly) covered … Continue reading →

Read more »

googleVis 0.4.3 released with improved Geocharts

June 18, 2013
By

The Google Charts Tools provide two kinds of heat map charts for geographical data, the Flash based Geomap and the HTML5/SVG based Geochart. I prefer the Geochart as it doesn't require Flash, but so far there have been two shortcomings with it: I couldn't add additional tooltip information and the default Mercator projection shows Greenland the...

Read more »

Software Packages for Graphs and Charts

June 17, 2013
By
Software Packages for Graphs and Charts

Graphs can be an important feature of analysis. A graph that has been well designed and put together can make summary statistics much more readable and increase the interpretability. It also makes reports and articles looks more professional. There are many software packages that are available to design great graphs and charts.  This seems to

Read more »

Computerworld’s Beginners Guide to R

June 17, 2013
By

Sharon Machlis is not only the online managing editor at Computerworld, she's also a budding data scientist who recently started learning the R language. To the benefit of all other new R users, she's shared her learnings in an excellent 6-part beginners guide to R, published by Computerworld. It's jam-packed with useful information for anyone getting started with R,...

Read more »