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I'm trying to build a simple routing web-app using pgrouting, followed some tutorial and the latest workshop. Because I'm using PostgreSQL 9.3(x64), Postgis 2.1.1, and pgrouting 2.0 so I did some modification to the PHP script so it can be used for my version. Here are the php code:

<?php

// Database connection settings
define("PG_DB"  , "db_mapserver");
define("PG_HOST", "localhost"); 
define("PG_USER", "postgres");
define("PG_PSSWD", "postgres");
define("PG_PORT", "5433"); 
define("TABLE",   "jalan1"); 

$counter = $pathlength = 0;

// Retrieve start point
$start = split(' ',$_REQUEST['startpoint']);
$startPoint = array($start[0], $start[1]);

// Retrieve end point
$end = split(' ',$_REQUEST['finalpoint']);
$endPoint = array($end[0], $end[1]);

// Find the nearest edge
$startEdge = findNearestEdge($startPoint);
$endEdge   = findNearestEdge($endPoint);

// FUNCTION findNearestEdge
function findNearestEdge($lonlat) {

// Connect to database
$con = pg_connect("dbname=".PG_DB." host=".PG_HOST." port=".PG_PORT." user=".PG_USER."    password=".PG_PSSWD);

$sql = "SELECT gid as id, source::int, target::int, geom, 
         st_distance(geom, ST_GeomFromText(
              'POINT(".$lonlat[0]." ".$lonlat[1].")', 4326)) AS st_dist 
        FROM ".TABLE."  
        WHERE geom && st_setsrid(
              'BOX3D(".($lonlat[0]-200)." 
                     ".($lonlat[1]-200).", 
                     ".($lonlat[0]+200)." 
                     ".($lonlat[1]+200).")'::box3d, 4326) 
        ORDER BY st_dist LIMIT 1";

$query = pg_query($con,$sql);  

$edge['gid']      = pg_fetch_result($query, 0, 0);  
$edge['source']   = pg_fetch_result($query, 0, 1);  
$edge['target']   = pg_fetch_result($query, 0, 2);  
$edge['geom']     = pg_fetch_result($query, 0, 3);  

// Close database connection
pg_close($con);

return $edge;
}

// Select the routing algorithm
switch($_REQUEST['method']) {

case 'SPD' : // Shortest Path Dijkstra 

  $sql = "SELECT rt.gid, st_AsText(rt.geom) AS st_wkt, 
               st_length(rt.geom) AS length, ".TABLE.".id 
            FROM ".TABLE.", 
                (SELECT gid, geom 
                    FROM pgr_dijkstra(
                        '".TABLE."',
                        ".$startEdge['source'].",
                        ".$endEdge['target'].",
                        3000)
                 ) as rt 
            WHERE ".TABLE.".gid=rt.gid;";
  break;

case 'SPA' : // Shortest Path A* 

  $sql = "SELECT rt.gid, st_AsText(rt.geom) AS st_wkt, 
                 st_length(rt.geom) AS length, ".TABLE.".id 
              FROM ".TABLE.", 
                  (SELECT gid as id, geom 
                      FROM pgr_astar(
                          '".TABLE."',
                          ".$startEdge['source'].",
                          ".$endEdge['target'].",
                          3000)
                   ) as rt 
              WHERE ".TABLE.".gid=rt.gid;";  
  break;
  } // close switch

  // Database connection and query
  $dbcon = pg_connect("dbname=".PG_DB." host=".PG_HOST." port=".PG_PORT." user=".PG_USER." password=".PG_PSSWD);

  $query = pg_query($dbcon,$sql); 

  // Return route as XML
  $xml  = '<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>'."\n";
  $xml .= "<route>\n";

  // Add edges to XML file
  while($edge=pg_fetch_assoc($query)) {  

  $pathlength += $edge['length'];

  $xml .= "\t<edge id='".++$counter."'>\n";
  $xml .= "\t\t<id>".$edge['id']."</id>\n";
  $xml .= "\t\t<wkt>".$edge['wkt']."</wkt>\n";
  $xml .= "\t\t<length>".round(($pathlength/1000),3)."</length>\n";
  $xml .= "\t</edge>\n";
  }

  $xml .= "</route>\n";

  // Close database connection
  pg_close($dbcon);

  // Return routing result
  header('Content-type: text/xml',true);
  echo $xml;

  ?>

I only modified the php code so it matches the postgis 2.x function and my own road network database. When I get into firefox and tried to compute the route, I got this error from Firebug:

pg_fetch_result(): Unable to jump to row 0 on PostgreSQL result index 3

Am I missing something? The route ran normally in QGIS DB Manager and pgAdmin.

glad to have a suggestion from you all

regards

UPDATE(3:22 pm GMT+7): I rebuilt my whole system, installing PostgreSQL 8.4, PostGIS 1.5, and pgrouting 1.x, using the original tutorial it still gave me the same error. I'm using openlayers as my map renderer.

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You get this error when there are no results, so the query returns 0 records, and row[0] does not exist. Using another postgres query method you can avoid this error:

$result = pg_exec($dbconn, $query);
$numrows = pg_numrows($result);

// Loop through rows in the result set
for($i = 0; $i < $numrows; $i++) 
{
    $row = pg_fetch_array($result, $i);
    echo $row["name"];
}

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