postgis 利用 php 返回geojson格式数据

<?php

/*
 * All database connection variables
 */
   $host        = "host=127.0.0.1";
   $port        = "port=5432";
   $dbname      = "dbname=soil";
   $credentials = "user=postgres password=123456";
?>

<?php

header("Access-Control-Allow-Origin: *"); 
 
require_once __DIR__ . '/db_config.php';

$dbconn = pg_connect("$host $port $dbname $credentials") or die('connection failed');

$result = pg_query($dbconn, "select id,name, ST_AsGeoJSON(geom) from nj_polygon");
if (!$result) {
  echo "An error occurred.\n";
  exit;
}
 
# Build GeoJSON
$output    = '';
$rowOutput = '';
// check for empty result
if (pg_num_rows($result) > 0) {
    // looping through all results 
    while ($row = pg_fetch_row($result)) {
        $rowOutput = (strlen($rowOutput) > 0 ? ',' : '') . '{"type": "Feature", "geometry": ' . $row[2] . ', "properties": {"id":"' .$row[0] .'","name":"' . $row[1] .'"}';
        $rowOutput .= '}';
        $output .= $rowOutput;
    }
    #echo json_encode($geojson, JSON_NUMERIC_CHECK);
    $output = '{ "type": "FeatureCollection", "features": [ ' . $output . ' ]}';
    echo $output;
} else {
    echo "no data";
}
pg_close($dbconn);
?>