gnuplot problems

danambroseUK has asked for the wisdom of the Perl Monks concerning the following question:

I have a script which has been working fine until last week and i dont know why.

$graph .= <<BLOCK;
set terminal png transparent
set output "tmp/$random.png"
set size 0.9,0.5
set pointsize 0
set xdata time
set format x "%a\\n%H:00"
set ylabel "Degrees C"
set xlabel "Hours"
set timefmt "%Y-%m-%d%H:%M:%S"
set key below
plot\\
BLOCK

foreach $i (@inputs){

$graph = $graph . "\"tmp/$random.dat\" using 1:" . $c . " title '$i' w
+ith lines,\\\n";

$c++;

}

$graph = substr($graph, 0, (length($graph)-3));

open (GNUPLOT, "|/usr/bin/gnuplot") or die $!;
print GNUPLOT $graph . "\n\n";
close (GNUPLOT);
[download]

sample datafile:

set terminal png transparent
set output "tmp/854.png"
set size 0.9,0.5
set pointsize 0
set xdata time
set format x "%a\n%H:00"
set ylabel "Degrees C"
set xlabel "Hours"
set timefmt "%Y-%m-%d%H:%M:%S"
set key below
plot\
"tmp/854.dat" using 1:2 title 'D4_AVG' with lines
[download]

The datafile is made fine, but no graph image file is produced. When i save $graph to file and then paste it to gnuplot on command line - its works fine. Your help would be great! Dan

Comment on gnuplot problems Select or Download Code

Replies are listed 'Best First'.
Re: gnuplot problems by Abigail-II (Bishop) on Apr 22, 2004 at 10:47 UTC
I think the problem is that you remove the final newline - and gnuplot uses newlines to terminate commands. If you cut-and-paste, such an action will introduce a terminating newline. Abigail	[reply]
Re: Re: gnuplot problems by danambroseUK (Beadle) on Apr 22, 2004 at 19:43 UTC
Surley the \n\n when $graph is printed will keep the required newlines in? Ive tried what has been mentioned - but the problem doesnt seem to be resolved. The thing is the script has been working fine for months until last week- when it decided not to work anymore! Am i opening and printing correctly to GNUPLOT? Thanks all, Dan	[reply]
Re: gnuplot problems by Fletch (Bishop) on Apr 22, 2004 at 14:28 UTC
And if you used `join` you wouldn't have to worry about incorrect trailing seperators. `$graph .= join( ", \\\n", map qq{"tmp/$random.dat" using 1:$_ title '$inputs[ $_ - 2 ] +' with lines}, 2..$#inputs+2 );` [download] Update: And of course you'd append a "\n" on the end of that otherwise you're right back where you were stuck before. %/	[reply] [d/l] [select]