use PDL;
	use PDL::Image2D;
	use PDL::IO::GD;

	my $data_pdl; #a pdl(289,145)
	my $interpolated_pdl = zeroes(21600,10800);
	bilin2n($interpolated_pdl,$data_pdl);

	my $range1 = ( $x >= 5 ) * ( $x < 10 );
	my $range2 = ( $x >= 10 ) * ( $x < 15 );
	my $range3 = $x >= 15;

	my $plotted_pdl = (     $range1 
	            + 2 * $range2
	            + 3 * $range3 )-> byte;

	my $palette = byte [ 
	    [   0,   0,   0 ],
	    [ 255,   0,   0 ],
	    [   0, 255,   0 ],
	    [   0,   0, 255 ]
	];

	my $plotted_image = PDL::IO::Image->new_from_pdl($plotted_pdl,$pallete);

	my $gd_image=PDL::IO::GD->new(pdl=>$plotted_image->pixels_to_pdl);

	#now all kinds of GD operations can be applied.