rows.php

<?php

$rows = range(0, 512);
$numRows = count($rows);
$degreesLatitude = 80;
$startLatitude = -90.0;
$factor = $degreesLatitude / $numRows;

array_walk($rows, function(&$value, $key) use ($startLatitude, $factor) 
{
	$value = $startLatitude + ($value * $factor);
});

var_dump($rows);