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Newsgroups: comp.graphics.apps.gnuplot
Date: Thu, 25 May 2017 17:31:08 -0700 (PDT)
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Subject: set the line colur value from a file
From: anees.alhamzawi@gmail.com
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Xref: csiph.com comp.graphics.apps.gnuplot:3649

Dear All,

I am trying to plot vectors with different colours. The colour value is stored as a third column in the data file.

For example, let us say the datafile is "a.tx" contains

0.603358	2.022173	1
1.08929	        2.039982	2
1.588976	2.040512	3

The typical plot is 

plot 'a.txt' using 1:1:($2-$1):(0) notitle with vectors heads size screen 0.008,90 lc 2

The question is that How could the "lc" has the third column value?