[vimeo 52312754]

(Video link here, in case the embedded player doesn’t work for you.)

Idea: see if I can mimic the idea behind Ben Schmidt’s lovely video of ocean shipping routes, and apply it to another dataset. But which?
“Hmm… what’s another interesting dataset about some competitors traveling around a mostly-fixed area at the same time?… Hey friends, stop  giving me election news, I need to think of an idea… Oh.” Continue reading “Animated map of 2012 US election campaigning, with R and ffmpeg” →

Thank you all for the positive responses to Basics of JavaScript and D3 for R Users! Quick update: last time we had to dabble in a tiny bit of Python to start a local server, in order to actually run JavaScript and D3 examples on our home computer… However, commenter Shankar had the great idea of using the R server instead. He provided some example code, but reported that it didn’t work with all the examples.

Here’s my alternative code, which works with all the D3 examples I’ve tried so far. Unlike Shankar’s approach with lower-level functions, I found it simpler to use Jeffrey Horner’s excellent Rook package.

# Load the Rook library
library(Rook)

# Where is your d3 directory located?
myD3dir <- 'C:/Downloads'

# Start the server
s <- Rhttpd$new()
s$start(quiet=TRUE)

# To view a different D3 example,
# change the directory and .html file names below
# and rerun s$add() and s$browse()
s$add(
app=Builder$new(
Static$new(
# List all the subdirectories that contain
# any files it will need to access (.js, .css, .html, etc)
urls = c('/d3','/d3/examples','/d3/examples/choropleth'),
root = myD3dir
),
Redirect$new('/d3/examples/choropleth/choropleth.html')
),
name='d3'
)
s$browse(2)
# browse(1) would load the default RookTest app instead

# When you're done,
# clean up by stopping and removing the server
s$stop()
s$remove(all=TRUE)
rm(s)

If I understand the Rook documentation correctly, you just can’t browse directories using R’s local server. So you’ll have to type in the exact directory and HTML file for each example separately. But otherwise, this should be a simple way to play with D3 for anyone who’d rather stick within R instead of installing Python.

Hadley Wickham, creator of the ggplot2 R package, has been learning JavaScript and its D3 library for the next iteration of ggplot2 (tentatively titled r2d3?)… so I suspect it’s only a matter of time before he pulls the rest of the R community along.

Below are a few things that weren’t obvious when I first tried reading JavaScript code and the D3 library in particular. (Please comment if you notice any errors.) Then there’s also a quick walkthrough for getting D3 examples running locally on your computer, and finally a list of other tutorials & resources. In a future post, we’ll explore one of the D3 examples and practice tweaking it.

Perhaps these short notes will help other R users get started more quickly than I did. Even if you’re a ways away from writing complex JavaScript from scratch, it can still be useful to take one of the plentiful D3 examples and modify it for your own purposes. Continue reading “Basics of JavaScript and D3 for R Users” →