Slopegraph:
- Suppose you have a table of two columns) and that you want to show graphically how the (two) elements of each row correspond in terms of value. A Slopegraph is useful in this context.
- The originator, Edward Tufte (http://www.edwardtufte.com), says (http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0003nk&topic_id=1) Slopegraphs compare changes over time for a list of nouns located on an ordinal or interval scale. Basically: Any time youd use a line chart to show a progression of univariate data among multiple actors over time, you might have a good candidate for a slopegraph. But some people have found it useful beyond this context.
Links:
- First saw it here: http://alex4d.wordpress.com/2011/07/14/fpx-july-2011-price-changes/
- This is a great example of its usefulness: price-spread variation (y-axis) over time (x-axis)
- Originator of this type of graph: http://charliepark.org/slopegraphs/
- He has implemented it in various tools.
- An R-Function (sourcecode) to do it: https://github.com/bobthecat/codebox/blob/master/table.graph.r
- I tried it and it works.
- e.g. [ table.graph(data.frame( Week1=0:9, Week2=c(1,3,5,7,11,13,17,19,23,29)) ) ]
- http://msenux.redwoods.edu/math/R/dataframe.php explains how to create dataframes in R
- OT: No idea if it can be conveniently done in Apple Mac’s Grapher, but here’s a link about that app: http://guides.macrumors.com/Grapher