use strict;
use warnings;
use PDL;
use PDL::IO::Image;

# data
my $x = sequence( 100, 100 );

# ranges
my $range1 = $x < 3000;
my $range2 = ( $x >= 3000 ) * ( $x <= 7000 );
my $range3 = $x > 7000;

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

my $palette = byte [ 
    [  0,   0,    0 ],
    [ 255,  50,  50 ],
    [ 128, 255,   0 ],
    [ 255, 215,   0 ]
];

$bytes-> wimage( 'test.png', { palette => $palette });

[download]

Not sure if I understand what you need, but, "from the top of my head", this code produces rather dull looking image with three colorful stripes (no time to invent some "smart" data). You have your conditions, combine them, associate with palette of the same length + 1.

In reply to Re^5: Interpolating data using pdl by vr
in thread Interpolating data using pdl by karthik248

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