gnuplot arrow coordinates (x,y) error columns

Question

I'm new in gnuplot and my aim is to plot arrows between each data coordinate. My ".dat" file has only two columns, separated by a single tab, where the first is the X and the second is the Y component. The head should be set in the next coordinate.

582.761 -326.288
574.806 -327.915

My command was:

plot 'file.dat' using 1:2 with vectors head filled

I only can obtain the following error message:

Not enough columns for this style

Sorry for the dumb question, but I couldn't understand neither the documentation nor other questions in the same subject.

Answer 1

If you check help vectors you will see that with vectors plotting style requires 4 values. And if I understand your question correctly I guess you want to plot arrows from one data line to the next data line, correct?

By the expression (x0=x1,x1=$1,x0) you keep the previous x value in x0 and the current value in x1, but you're plotting x0. Same for y0 and y1. And (x1-x0) and (y1-y0) are simply the delta x and delta y values which you need for the with vectors plotting style.

Code:

### vectors from data line to the next
reset session

$Data <<EOD
1   1
2   2
3   5
2   4
1   2
EOD

x1=y1=NaN
plot $Data u (x0=x1,x1=$1,x0):(y0=y1,y1=$2,y0):(x1-x0):(y1-y0) w vectors head filled notitle

### end of code

Result: