R: plotting with the ggplot2 package

R: plotting with the ggplot2 package

While crunching numbers, a visual analysis of your data may help you get an overview of your data or compare filtered information at a glance. Aside from the built-in graphics package, R has many additional packages to help you with that.
We want to focus on ggplot2 by Hadley Wickham, which is a very nice and quite popular graphics package.

Ggplot2 is based on a kind of statistical philosophy from a book I really recommend reading. In The Grammar of Graphics, author Leland Wilkinson goes deep into the structure of quantitative plotting. As a product, he establishes a rulebook for building charts the right way. Hadley Wickham built ggplot2 to follow these aesthetics and principles.

Your first interactive choropleth map with R

Your first interactive choropleth map with R

When it comes to data journalism, visualizing your data isn’t what it’s all about. Getting and cleaning your data, analyzing and verifying your findings is way more important.

Still, an interactive eye-catcher holding interesting information will definitely not hurt your data story. Plus, you can use graphics for a visual analysis, too.

Here, we’ll show you how to build a choropleth map, where your data is visualized as colored polygon areas like countries and states.
We will code a multilayer map on Dortmunds students as an example. You’ll be able to switch between layered data from different years. The popups hold additional information on Dortmunds districts.

R crash course: Basic data structures

by Sakander Zirai 1 Comment
R crash course: Basic data structures

 

„To understand computations in R, two slogans are helpful: Everything that exists is an object. Everything that happens is a function call.“John M. Chambers

Data structures in R are quite different from most programming languages. Understanding them is a necessity, because they define the way you’ll work with your data. Problems in understanding data structures will probably also produce problems in your code.

R crash course: Writing functions

by Kira Schacht 0 Comments
R crash course: Writing functions

As you know by now, R is all about functions. In the event that there isn’t one for the exact thing you want to do, you can even write your own! Writing your own functions is a very useful way to automate your work. Once defined, it’s easy to call new functions as often as you need. It’s a good habit to get into when programming with R — and with lots of other languages as well.

Defining a function uses another function simply called function(). Function names follow pretty much the same rules as variable names, so you can call them anything that would also be acceptable as a variable name.

R exercise: Analysing data

R exercise: Analysing data

While using R for your everyday calculations is so much more fun than using your smartphone, that’s not the (only) reason we’re here. So let’s move on to the real thing: How to make data tell us a story.

First you’ll need some data. You haven’t learned how to get and clean data, yet. We’ll get to that later. For now you can practice on this data set. The data journalists at Berliner Morgenpost used it to take a closer look at refugees in Germany and kindly put the clean data set online. You can also play around with your own set of data. Feel free to look for something entertaining on the internet – or in hidden corners of your hard drive. Remember to save your data in your working directory to save yourself some unneccessary typing.

R crash course: Workspace, packages and data import

by Kira Schacht 3 Comments
R crash course: Workspace, packages and data import

In this crash course section, we’ll talk about importing all sorts of data into R and installing fancy new packages. Also, we’ll learn to know our way around the workspace.

Your workspace in R is like the desk you work at. It’s where all the data, defined variables and other objects you’re currently working with are stored. Like with a desk, you might want to clean it every once in a while and throw out stuff you don’t need any more. There’s a few useful commands to help you do that. Take a look and try them out:

R crash course: Vectors

R crash course: Vectors

Now that you installed RStudio, learned about assignments and wrote some basic code, there’s nothing stopping you from becoming a journocoder!

To get a deeper understanding of how R stores your data, we’re now going to take a closer look at data structures in R, starting with a central concept: Vectors.

Working with vectors

R crash course: Getting started

At journocode, we’re starting out with an intro to the tool we rely on most right now: The statistical programming language R. “R: A Language for Data Analysis and Graphics” is mostly used in statistics, but is very useful for journalists working with data as well.

You can install R here. Since it is open source, there are tons of packages with additional functions and possibilities. We will show you how to find and install them in the next chapters.