Computation Wesley R. Elsberry on 29 Jan 2008 06:59 am
How does one plot 5.2 million XY data points?
I ran into this while working on a paper submission. This is one thing one does not lack for when doing evolutionary computation: size of data sets.
Matlab seems to become dog slow and unstable when trying to plot large numbers of data points. The interface bogs down such that trying to re-label axes is a real chore.
I tried out the GNU R package, and had it crash on trying to read in the data set.
Then I started going through plotting packages in the FreeBSD ports system. That’s where I came across the GRI package. This is an open source, GPL licensed graph plotting language. It has simple examples available online. As its documentation notes, it is a package with a fairly shallow learning curve. Its interface is entirely command-line, and its output option is PostScript. In interaction, it simply outputs PostScript graphic after Postscript graphic, simply named “gri-nn.ps” in the current working directory. One can import data from an ASCII file, where columns are separated by white space.
So that’s exactly what I did. 5.2 million data points in, one 151MB Postscript graphic out. Ghostscript can convert that to PDF, which can then be converted to all sorts of raster-based graphics formats. It’s not a perfect solution, but it is a working solution.
Back to the grind for me…<= get_option(\'vc_tag\') ?>> = get_option(\'vc_text_before\') ?> 5725 = get_option(\'vc_human_count_text_many\') ?> = get_option(\'vc_preposition\') ?> 2424 = get_option(\'vc_human_viewers_text_many\') ?> = get_option(\'vc_tag\') ?>>