Re: [Gnuplot-info] gnuplot xtic question

[<br...@ph...>]

Jonathan Lynch wrote:

> There are potentially ten data points in the space of a second. If i
> express time in the format 16:19:25.941980 the graph is inaccurate
> because gnuplot does not support fractions of a second due to using the
> tm structure.

It'll only be inaccurate if a second is still wider than one pixel on 
the actual output format.  Whether that's the case depends on the output 
format, and the length of the interval you have measurements for.

> So Im going to stick to plotting the floating point data. Gnuplot
> generates tics on the x-axis and labels them. What is the algorithm
> where gnuplot calculates where the tics should be?

It's complicated.  The general scheme is: "divide the range into
intervals of 'nice' length, such that there are between 5 and 10 of them"

> I could write a C program to parse through the data file and generate a
> file with gnuplot commands. if i knew exactly where the tics were going
> to be I could put some tics manually eg.
> set xtics ("16:19:25",58765.0, 16:19:30",58770.0) and so on.

Why do you think you have to know the tick placement for that?  This 
command will override the automatically placed tick positions, so it 
doesn't matter where they would have gone.