<?php
ini_set('memory_limit', '-1');
ini_set('max_execution_time', 300);
error_reporting(0);

// open the file
$file = file_get_contents('glds00g.asc');

// put lines in an array
$lines = explode("\n", $file);

// first few lines are irrelevant
for($i=0;$i<6;$i++)
    unset($lines[$i]);

$count =array();

// the catogories. So from 6000 to 8000 people per square km fit in catogory P for example.
$cats = array(
    '0'=>0,
    '1'=>0.5,
    '2'=>1,
    '3'=>3,
    '4'=>5,
    '5'=>10,
    '6'=>25,
    '7'=>50,
    '8'=>100,
    '9'=>150,
    'a'=>200,
    'b'=>300,
    'c'=>400,
    'd'=>500,
    'e'=>600,
    'f'=>800,
    'g'=>1000,
    'h'=>1250,
    'i'=>1500,
    'j'=>1750,
    'k'=>2000,
    'l'=>2500,
    'm'=>3000,
    'n'=>4000,
    'o'=>6000,
    'p'=>8000,
    'q'=>10000,
    'r'=>25000,
    's'=>50000,
    't'=>10000000,
    );

// find the catogory for a value
function popcat($a)
{
    global $count;
    global $cats;
        foreach($cats as $key=>$cat)
        {
            if($a<$cat)
            {
                return $key;
                break;
            }
        }
}


// run trough all lines and all values
$line_content = array();
foreach($lines as $key=> $line)
{
        $items = explode(' ',$line);

        foreach($items AS $item)
            $line_content[$key] = $line_content[$key].popcat($item);
        $line_content[$key] = substr($line_content[$key], 0, strlen($line_content[$key])-1).PHP_EOL;

}

// save the data
$fp = fopen('compressed.log', 'w');

        fwrite($fp, implode('', $line_content));
        fclose($fp);