Question

I want gnuplot to plot an irregular timeseries as bars, but my bars are always placed at day boundaries (the midnight marks), as if the time info were ignored (e.g. the first two entries show up on top of each other at midnight). The days are spaced widely enough, it’s not an issue of the bars being too scrunched up. Sample data:

07/09/2012-00:00 1 741 0.50
07/09/2012-12:00 2 3087 0.50
07/12/2012-00:00 1 2011 0.33
07/12/2012-08:00 2 814 0.33
07/12/2012-16:00 2 99 0.33

The relevant gnuplot code below. The xtics settings are just for aesthetics, they have no bearing on the issue.

set xdata time
set timefmt "%m/%d/%y-%H:%M"
set xtics format "%m/%d"
set xtics "07/08/2012-00:00", 2*172800 ,"08/28/2012-00:00"
plot FILE using 1:3:2 with boxes lc variable

Two separate, but related questions: 1) Can I remove the leading zeros from x-axis labels (i.e 7/8, not 07/08) to save space (“%m” and “%d” always give me leading zeros)? 2) Can I vary the width of a bar based on data from file (in this case, I’d like the 4th column to be a fractional multiplier for the standard bar width)? Thanks.

Answer 1

Your time format is wrong. you want %Y (4-digit year) instead of %y (2-digit year).

In order to specify the width, you’ll need 4 columns of data:

plot FILE using x_column:y_column:x_width:linestyle w boxes lc variable

where x_width is the width of the box in seconds (since that is the unit on a time-axis).