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

Monks, I'm a bit rusty with Perl, I took a hiatus to learn TCL. I'm having an issue with Chart::Graph::Gnuplot, today. Using the General Example from CPAN, I always seem to return an error message, I'm fairly certain that I'm passing the data set as an array, though I may be smoking the crack.. Error: 
Data set must be an array at gnuplot.cgi line 9

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General Example 
  use Chart::Graph::Gnuplot qw(gnuplot);
  gnuplot({"title" => "foo",
           "x2-axis label" => "bar",
           "logscale x2" => "1",
           "logscale y" => "1",
           "output type" => "png",
           "output file" => "gnuplot1.png",
           "xtics" => [ ["small\\nfoo", 10], ["medium\\nfoo", 20], ["l
+arge\\nfoo", 30] ],
           "ytics" => [10,20,30,40,50]},
           "xdata" => "time",
           "format" => ["x", "%m/%d"],
           "timefmt"=> $date_format,
           "extra_opts" => "set key left top Left",
          [{"title" => "data1",
            "type" => "matrix"}, [[1, 10],
                                  [2, 20],
                                  [3, 30]] ],
          [{"title" => "data2",
            "style" => "lines",
            "type" => "columns"}, [8, 26, 50, 60, 70],
                                  [5, 28, 50, 60, 70] ],
          [{"title" => "data3",
            "style" => "lines",
            "type" => "file"}, "samplefile"],);

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Any help is apreciated!

--
paul

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Re: Chart::Graph::Gnuplot Array Issue
by naChoZ (Curate) on Jul 21, 2004 at 23:11 UTC

    You can do it without necessarily bothering with that module. Abigail-II told me how he does it, so here's a snippet I wrote. 

        # {{{ ->create graph method
    # 
    sub create_graph {
        my $class = shift;

        open my $plot => "| /usr/local/bin/gnuplot" 
            or die "Failed to open pipe: $!\n";

        my $outfile = "/tmp/graph.png";
        print $plot <<"        --";
        set  terminal png color
        set  out "$outfile"
        set  format x "/%b%y/"
        set  xdata  time
        set  key left top Left reverse samplen 2 title "Legend" box
       
        set  timefmt "%s:"

        set  grid   xtics ytics
        set  xtics  nomirror
        set  ytics  nomirror
        set  y3tics nomirror

        set  autoscale

        set  ylabel "ResponseTime"
        plot "$_[0]" using 1:2 smooth unique axis x1y1 title "Time in 
+ms"
        --
        #set   timefmt "%Y-%m-%d:"
        close $plot or die "Failed to close pipe: $!\n";
        chmod 0644 => $outfile or die "Failed to chmod $outfile: $!\n"
+;

    } # }}}

    [download]
    I just pass it a filename (which I had previously created with File::Temp). My::Class->create_graph( $filename );

    --
    "A long habit of not thinking a thing wrong, gives it a superficial appearance of being right." -- Thomas Paine
    naChoZ

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      DUDE, YOU ROCK! Thanks a lot!

      --
      paul

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Re: Chart::Graph::Gnuplot Array Issue
by vbrtrmn (Pilgrim) on Jul 22, 2004 at 18:24 UTC
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Re: Chart::Graph::Gnuplot Array Issue
by kryberg (Pilgrim) on Jul 22, 2004 at 18:31 UTC
    I've done it another way from the one already suggested.

    I use LWP::UserAgent to get data from a URL, save it to a file because it is a very large dataset I use more than once, do a bunch of manipulations, ultimately putting the data into arrays (@dates and @atemp in the code below) for various graphs, then graph.

      gnuplot({
        "title" => "",
        "output type" => "png",
        "output file" => "temp.png",
        "x-axis label" => "$day.$month.$year $time - $eday.$emonth.$ey
+ear $etime",
        "y-axis label" => "",
        "xdata" => "time",
        "format" => ["x", "%d.%m"],
        "timefmt" => "%Y-%m-%d-%H:%M",
        "xrange" => "[\"$dates[$index]\" : \"$dates[$j]\"]",
        "extra_opts" => join("\n","set grid", "set nokey", "set linest
+yle 1 lt 3 l
w 10","set lmargin 10","set rmargin 10","set tmargin 9","set bmargin 9
+" )},
        [{
        "style" => "lines ls 1",
        "type" => "columns"}, [@dates],[@atemp] ],);
  my $type = "AirTemp.png";
  my $ftype = "Days" . "$days" . "ATemp.png";
  my $finalgraph = printGraph($station,$type,$ftype);
}

    [download]
    In case anyone notices/wonders/tries to use this, some things are intentionally left blank and the file is called temp because I ultimately use GD to splice this onto a background image using the subroutine at the end called printGraph - I just thought I'd include the whole code block because I know it works.
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