I have received several requests for additional LSPM documentation over the past couple days and a couple months ago I promised an introduction to LSPM. In this long-overdue post, I will show how to optimize a Leverage Space Portfolio with the LSPM pa...
The R statistical computing environment is awesome, but weird. How to do database operations in R is a common source of questions. The other day I was looking for an equivalent to SQL group by for R data frames. You need this to compute summary statist...
One of the problems with choropleths is that, as explained by Hadley Wickham in this presentation, big states tend to draw more attention because of their size, but they also tend to have a low population Density. For example, Mexico City, the capital ...
The 40 Republican senators currently in the U.S. senate represent 36% of the U.S population. See the graph below (click on the thumbnail for PDF). This is something I’ve been meaning to compute for a while now, mapping the cumulative distribution of senators’ ideal points onto the cumulative distribution of state population (each state counts
It’s Christmas Eve tomorrow and so I declare the year over. My Christmas gift to you is a summary of activity in 2009 at the FriendFeed Life Scientists group. It’s crafted using R + Ruby, with raw data and some code snippets available. If you want to see the most popular items from the group 
What has been the impact of the economic crisis on employment? And how has it affected the different regions of Mexico? To answer the questions the first step was to obtain the unemployment data from the Banco de Información Económica at the INEGI. ...
Over the next few posts, I’m going to be reviewing the use of R to implement the most commonly used matrix techniques for image manipulation. The code will be surprisingly simple to understand, because the real magic behind these techniques lies in the mathematics that R provides an abstract interface to. To start, I’m going
Just about everyone is familiar with weather maps. There are many situations where it is useful to combine the underlying numerical weather data with other types of information. Accessing the weather data is a necessary first step. The output from the U.S. National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) is freely available.
I was prompted by a thread on the apparent decline of FriendFeed to look for evidence of declining participation in my networks. First, a quick and dirty Ruby script, tls.rb to grab the Life Scientists feed and count the likes and comments: #!/usr/bin/ruby require 'rubygems' require 'json/pure' require 'net/http' require 'open-uri' def format_date(d) if d 
Premise
I was recently asked to print out a fabric pattern that could be used to cover a sphere, about the size of a ping pong ball, for the purposes of re-creating a favorite cat toy (quite important). Thinking this over, I realized that this was basically a map projection problem-- and could probably be solved by scaling...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
