On 2026-02-06 09:33, Chris Green wrote:
Roland Müller <[email protected]> wrote:
Hello,
On 2/4/26 11:06, Chris Green wrote:
> I'm looking for a program to do simple chart plotting, e.g. I have
> some voltage measurements taken (say) once a minute and I want to
> display how the voltage varies over (say) a day. So that's 1440
> measurements.
There is gnuplot as already mentioned but there are other tools too.
Pandas: this supports many other data analysis functionality
https://pandas.pydata.org/docs/reference/plotting.html
https://blog.jetbrains.com/pycharm/2023/02/using-pycharm-to-read-data-from-a-mysql-database-into-pandas/
Grafana; a data visualization tool with a lot of feature both for
plotting/visualization and using data sources
https://grafana.com/docs/grafana/latest/datasources/
Hmm, I took a look at that, it's **huge** and **complex**. All I want
to do is plot values against time, grafana is massive overkill for
doing that.
Sorry I sent this to you instead of the list earlier.
I'd have thought if you have a CSV file values per line you could get
that into an array with Perl
Text::CSV and make a visual representation putting dots on a TK canvas.
even easier would be to get the CSV file into an array and then use
Imlib2 to draw points and save as a png.
perl
use Image::Imlib2;
# get CSV into @my_array here
my $width = 1440;
my $height = 600;
# make a background
my $im = Image::Imlib2->new($width, $height);
$im->set_color(255,255,255,255); # white background
$im->fill_rectangle(0,0,$width,$height);
# this will have 0,0 in the top left corner
$im->set_color(0,255,0,255);
for my $x (0..$#my_array) {
my $y = $my_array[$x];
$im->draw_point($x, $y);
}
$im->save("out.png");
