Re: [Gnuplot-info] Plot time series with different colored points

[Ethan A M. <eam...@gm...>]

On Saturday, 26 December 2015 08:10:21 PM sfg...@gm... wrote:
> Hi folks,
> 
> I want to plot time series data where the color of a point depends on
> the hour the data is  measured (0 to 23 hour). But I can't figure out
> how to do this. Here is my example:
> 
> reset
> set xlabel "Date"
> set xdata time
> set timefmt '"%Y-%m-%d %H:%M"'
> set format x "%m-%d"
> set xtics nomirror
> set ylabel "Y"
> set palette model RGB defined ( 0 'green', 23 'blue' )
> set cbrange [0:23]
> 
> T(N) = tm_hour(timecolumn(N,'"%Y-%m-%d %H:%M"'))
> 
> plot '-' u 1:2:T(1) with linespoints axis x1y1 title 'Y' ps 2 lw 2 palette
> "2015-12-15 Tue 07:40" 2.4  
> "2015-12-15 Tue 21:48" 1.7  
> "2015-12-16 Wed 08:13" 2.5  
> "2015-12-17 Thu 08:54" 2.6  
> "2015-12-17 Thu 21:41" 2.2  
> "2015-12-18 Fri 08:05" 2.1  
> "2015-12-19 Sat 10:35" 3.6  
> "2015-12-20 Sun 11:40" 3.6  
> "2015-12-21 Mon 09:32" 4.5  
> EOF
>  
> I got "unknown type in magnitude()" error. Any hints how to resolve
> this? Thanks, Sven

There are several syntax errors there.
I won't fix them all but here's a variant that works:

H(N) = int(strcol(N)[16:*])
plot '-' u 1:2:(H(1)) with linespoints title 'Y' ps 2 lw 2 lc palette