<?php

$str  = "-638,-663,28 + 180,-60,50 + 838,-473,22 + 21,230,11 + 35,162,28 + 88,-33,22 + -346,632,22";
$coords = explode("+", $str);
$i=0;
foreach($coords as $coord){ 
    $i=$i+1;
       echo $i." - ".$coord;
    
    }
    

?>