Why gnuplot rounds data in column of vertical axis? - gnuplot

Question

My old script worked fine years ago.
set terminal png background "#ffffff" enhanced fontscale 2.0 size 1800, 1400
set output 'delete.png'
w=1
x=1
z = 60
y=2
plot 'plot.in.tmp' using (column(x)/z):(column(y)) axis x1y1 with lines
exit gnuplot
reset
Now result in graph with only rounded integer points in y(vertical) axe. I dont understand why.
Example data in file:
0 -0,00 0,5 570,2 11,98 -0,121 0,000 9,6
5 -0,00 0,7 570,2 11,97 -0,002 0,012 13,2
10 -0,00 0,9 570,3 11,98 -0,004 -0,000 16,1
15 0,24 35,9 570,4 11,96 0,001 0,000 18,4
20 0,56 87,0 570,1 11,99 -0,001 -0,000 20,5
25 1,03 173,5 570,4 11,97 -0,000 0,000 23,2
30 1,61 296,4 570,3 11,96 0,002 0,000 12,4
35 2,17 422,6 570,2 11,68 0,004 0,000 8,8
40 2,81 571,6 570,2 11,37 0,010 0,001 7,5
45 3,52 752,3 570,3 11,26 0,015 0,000 7,1
50 3,97 905,0 570,2 11,69 0,075 0,006 7,4
55 4,36 1048,4 570,1 11,36 0,081 0,001 8,6
60 4,59 1156,8 570,2 11,22 0,087 0,001 10,7
Result graph:

Answer 1

Welcome to StackOverflow! Maybe the local setting of your system (or something in gnuplot) has changed?
The following works for me with your data.
Add a line
set decimalsign locale "german"
or
set decimalsign locale "french"
Check help decimalsign.
Syntax:
set decimalsign {<value> | locale {"<locale>"}}
Correct typesetting in most European countries requires:
set decimalsign ','
Please note: If you set an explicit string, this affects only numbers
that are printed using gnuplot's gprintf() formatting routine,
including axis tics. It does not affect the format expected for input
data, and it does not affect numbers printed with the sprintf()
formatting routine.

Answer 2

The answer given by theozh is correct, but it does not point out the unfortunate lack of standardization about how different operating systems report the current locale setting. For linux machines the locale strings are less human-friendly. For example instead of using something generic like "french", they subdivide into "fr_FR.UTF-8" "fr_BE.UTF-8" "fr_LU.UTF-8" etc to account for slight differences in the conventions used in France, Belgium, Luxembourg, etc.
I cannot tell you the exact set of locale descriptions on your machine, but here is what works for me on a linux machine:
set decimalsign locale "fr_FR.UTF-8"
w=1
x=1
z = 60
y=2
plot 'plot.in.tmp' using (column(x)/z):(column(y)) axis x1y1 with lines