I can't figure out why this happens, but some of my plots have a yrange that goes all the way to zero even though the data is only between 15-30. I originally tried this on v5.3 and then tried it on v5.5 and got the same results.
I've attached both a input file that reproduces this result and the SVG file that is produced when I run it on my machine.
I'm running "Version 5.5 patchlevel 0 last modified 2020-08-01" (just build from source today) on Linux Mint 20.
I am not entirely sure why this happens, but the basic issue is that the "filledcurves" plot style has several variants. You want your data to be treated as a closed curve, which the documentation claims is the default for 2-column data, but for some reason the program is not entirely honoring this. If you change the plot command to:
i.e. add the keyword
closedthen it will behave as you expected.Thank you for the bug report.
Thank you for the suggestion. That does seem to work, but only for the version I've built from source. When I use v5.3 (shipped with my OS), then adding the "closed" doesn't seem to help.