barty

BARTY

This plugin is known as barty (for BART-year, as opposed to our first BART plugin, which has data for only one day).

BARTy gives users access to (at this writing) one year of BART data: for each hour, and each pair of stations, you can learn the number of people who entered the system at the first station and exited at the second. This works out to over 10 million cases.

The designer's task, therefore, is to give users easy-to-understand access to this large data set, and to give them useful choices about what cases to download, when they can only practically work with a few thousand cases at a time.

Why barty is so cool for DSE

The data are more multidimensional than they sound, so users have to think hard about what data to ask for; and then CODAP gives them the chance to fix their mistakes easily and improve what they are doing. Also, because of that multidimensionality, there are many ways to organize data and compute aggregate measures. So there is a lot of flexibility in what data moves are possible or useful.

For example, suppose you have the task of figuring out how many people took BART to attend Pride, which is on a Sunday in June. You need to conider questions such as

• What destination stations should you look at?
• Do "source" stations matter?
• What times should you look at?
• So you look at arrivals or departures or both?
• Should you compare the data with a non-pride day? Which day? Only one?

Of course, Tim prefers that we not give students these questions but let them come up with them themselves in a process of looking critically at partial solutions.

The files