Thanks again for the help. My attempt to speed up Ham::WorldMap by hacking Imager only doubled the speed. Swapping out setpixel for setscanline in sub _moveterm takes the synopsis code from 6 seconds to 1 local second. Here's my implementation: 
use Ham::WorldMap; 
# replace _moveterm with __moveterm for huge speed gain
{ no strict 'refs'; *{"Ham::WorldMap" . '::' . "_moveterm"} = \&__move
+term }


# __moveterm(wtab, noon, width, height) - update illuminated portion o
+f the globe.
# Speed fix from: https://www.perlmonks.org/index.pl?node_id=11148856
sub __moveterm {
    my ($wtab, $noon, $width, $height) = @_;
    my $illumMap = Imager->new(ysize => $height, xsize => $width);
    $illumMap = $illumMap->convert(preset => 'addalpha');
    my $day_p = pack 'C4', 255, 255, 255, 10;

    for (my $i = 0; $i < $height; $i++) {
        if ($wtab->[$i] >= 0) {
            my $nl = (($noon - ($wtab->[$i] / 2)) + $width) % $width;
            my $nh = ($nl + $wtab->[$i]) - 1;
            my $oh = ($nh - $nl) + 1;
            
            if (($nl + $oh) > $width) {
              $illumMap->setscanline(x => $nl, y => $i, pixels => $day
+_p x ($width - $nl));
              $illumMap->setscanline(x => 0,   y => $i, pixels => $day
+_p x ($nl + $oh - $width + 1));
            } else {
              $illumMap->setscanline(x => $nl, y => $i, pixels => $day
+_p x ($oh + 1));
            }
        }
    }
    return $illumMap;
}

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In reply to Re: Double the speed of Imager->setpixel by Anonymous Monk
in thread Double the speed of Imager->setpixel by Anonymous Monk

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