Why doesn't the gnuplot grid extend over this whole plot?

5
votes

Using gnuplot 4.6 patchlevel 1, with the following commands,

set grid linewidth 1 linecolor rgb"#888888"
set datafile separator ","
plot for [n=2:100] "data.csv" using 1:(column(n)) with lines linewidth 2

and the following example data in the file "data.csv",

time,S1,S2
0,0.00015,0
0.1,0.0001357256127053939,1.427438729460607e-005
0.2,0.0001228096129616973,2.719038703830272e-005
0.3,0.0001111227331022577,3.887726689774233e-005
0.4,0.0001005480069053459,4.945199309465411e-005
0.5,9.097959895689501e-005,5.902040104310499e-005
0.6,8.232174541410396e-005,6.767825458589604e-005
0.7,7.448779556871142e-005,7.551220443128858e-005
0.8,6.739934461758323e-005,8.260065538241677e-005
0.9,6.098544896108986e-005,8.901455103891014e-005
1,5.518191617571635e-005,9.481808382428365e-005

the resulting plot looks this:

enter image description here

Question: why does the grid only extend partway from the bottom, and not cover the whole plot? I tried a considerable amount of experimentation with the set xtics and ytics commands, arguments to grid, and more, and have not been able to get the grid to cover the whole plot. What am I missing?

1
gnuplot
Which OS/terminal and version of gnuplot are you using? The grid looks fine for me (covering the whole plot) using the data and commands you provided. I am running Arch Linux/gnuplot 4.6.1 and using the png and eps terminals. - andyras
I'm using the MacPorts version of gnuplot (the version identifier reads as "4.6.1_0+aquaterm+luaterm+pangocairo+x11") on Mac OS X 10.8.2 system. It happens to me whether I use the SVG terminal or the Aqua terminal. I just tried the PNG terminal, but it happens with that too. Hmmm. But the fact it doesn't happen to you is very interesting. - mhucka
@andyras -- Try it with the x11 terminal (I was able to reproduce it on OS-X 10.5.8) - mgilson
I just gave it a try, and I also have the grid covering the complete plot. Using gnuplot 4.4 patchlevel 4 on a linux machine... and @mgilson: I cannot reproduce it with x11 terminal - Woltan
@Woltan -- What terminal? I can reproduce this using the x11 terminal using gnuplot 4.6.0 (OS-X 10.5.8) and gnuplot 4.6.1 (Ubuntu Linux) - mgilson

1 Answers

2
votes

Great question! In fact, the answer is that the grid does cover the whole plot. The problem is that the key is taking over. Try it again, but with an unset key in there before your plot command.

What's happening is that gnuplot is reserving space in the key for all of the columns which have no data. Nothing gets put in the space that was reserved since no reasonable data was found. Ultimately, this pushes the 2 lines that were visible out of the viewable canvas area as well.

I've reproduced this using the x11, png, postscript and pngcairo terminals.

Note that this behavior seems to be version dependent:

With gnuplot 4.4.2 (OS-X, png terminal)

enter image description here

With gnuplot 4.6.0 (OS-X, png terminal)

enter image description here

For those using gnuplot 4.4.4, perhaps there was a bug fix which made it work for gnuplot 4.4.4 and then a regression. It seems to persist into gnuplot 4.7.0 as well. I might file a bug report.