Good Looking Maps in R

I haven't yet tried this, but it looks like a nice package.

In one recent project I needed to draw several maps and visualize different kinds of geographical data on it. I found the combination of R/ggplot/maps package extremely flexible and powerful, and produce nice looking map based visualizations.

Here is a short tutorial, monospace font indicates the code you need to run in R. You probably need some basic understanding of R to work through this tutorial.

Enjoy!

Computing Statistical Power

Today's task is to compute a statistical power function in R. For a good definition of power, go here. Thinking about the power of a testing procedure is an often-overlooked aspect of hypothesis testing.

I also explain what power (in a statistical sense) is in the video, as well as use my shadenorm() function to show what power looks like on the classical hypothesis testing graph. Along the way, I demonstrate how writing a function can make your life easier. Here's the video:



Here is the script file I walk through in the video (copy into notepad for a better view):



My script file uses a new version of my shadenorm() command that is a little easier to use (only change: now, there are no justbelow or justabove arguments. If you just specify below, that's justbelow=TRUE...).

This is available here:

How did I make this plot?

To make this plot, I used R's plot(), points() and lines() commands. If you have been wanting to learn how to plot in R, watch it unfold in this video tutorial:



Also, here's the code I used:

How to Shade Under a Normal Density in R

The easiest-to-find method for shading under a normal density is to use the polygon() command. That link is to the first hit on Google for "Shading Under a Normal Curve in R." It works (like a charm), but it is not the most intuitive way to let users produce plots of normal densities.

In response to the standard polygon() approach, I wrote a function called shadenorm() that will produce a plot of a normal density with whatever area you want shaded. The code is available here (in a newer post; I updated the function slightly).

Copy into an R script and run all of it if you want to use the shadenorm() command. To show you how to use it, I also recorded a video tutorial in R to demonstrate how to use the shadenorm() command.




Here is the code I use in the video:



There are a lot of applications where you may want to produce a plot with a normal density with some region shaded. I hope you find this function useful.

Basic Plots in R

Here's a tutorial I recorded on producing basic plots in R.



I lost the script file I used to create the video to a horrifying black screen of death, but I used the data from the previous post (available here). Hopefully, the video is clear enough that you can follow along with your own window of R.