This morning I wrote up this quick and easy way to get actual numbers out of graphs and whatnot that show up in journal articles.

$ pdfimages article.pdf fig
$ fig-000.ppm > fig-000.pixels
$ 0 10 5 20 fig-000.pixels >

Just use your first four clicks in to mark out the x and y minimum and maximum values. Then use scale to convert the pixel values to the units listed in the figure. In my example, the x axis ran from 0 to 10 units, and the y axis ran from 5 to 20 units. Supports log-scaled axes too.

Having gotten some numbers, my sawtooth simulator matches up fairly well to Schlierf & Rief's results on both models. Hooray! ;).