GIS and Media fusion

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geoinf17:geoservice0

Géoservice Get4Capitals.php

Cet exemple montre comment créer un service sur mesure qui va publier l'information géographique de la géotable. Il est notamment fait usage du format GeoJSON pour transmettre ces données au client. OpenLayers saura par exemple l'exploiter facilement au travers d'une couche ol.Vector et le format ol.format.GeoJSON.

<?php
require_once 'GeoManager.php';
$conn = new Connection("host=127.0.0.1 port=5432 dbname=php user=admintoto password=blablatutu");

$query = "SELECT name, ST_AsGeoJSON(the_geom) from my4capitals";
$result = $conn->selectQuery($query);

$i = 0;
$fc = new FeatureCollection();
while ($row = pg_fetch_row($result)) {
    $fc->addFeature(new Feature($i++, (json_decode($row[1])), array("name" => $row[0])));
}
echo json_encode($fc);
?>

On a besoin d'un GeoManager (GeoManager.php) qui sait gérer les requêtes avec la geodatabase et encoder les résultats par un flux GeoJSON.

<?php
class Connection {

    private $CONFIG;
    private $CONN;

    function __construct($cfg) {
        $this->CONFIG = $cfg;
        return $this->CONN = pg_connect($this->CONFIG) or die('connection failed');
    }

    function selectQuery($query) {
        $result = pg_query($this->CONN, $query);
        if (!$result) throw new ErrorException($query);
        return $result;
    }

    function insertQuery($query) {
        pg_query($this->CONN, "BEGIN WORK");
        $result = pg_query($this->CONN, $query);
        if (!$result) {
            pg_query($this->CONN, "ROLLBACK");
        } else {
            pg_query($this->CONN, "COMMIT");
        }
    }
}

class Feature
{
	var $type;
	var $geometry;
	var $id;
	var $properties;

	function Feature($id,$geom,$properties) {
		$this->type = "Feature";
		$this->geometry = $geom;
		$this->id = $id;
		$this->properties = $properties;
             
	}
}

class FeatureCollection
{
	var $type;
	var $features;
	
	function FeatureCollection()
	{
		$this->type = "FeatureCollection";
		$this->features = array();
	}
	
	function addFeature($feature) {
		array_push($this->features,$feature);
	} 
}
?>

TODO

  1. Tester ce géoservice et analyser les différentes étapes du processus (veiller à reconfigurer les paramètres de connexion) - évt utiliser l'astuce de Daniel http://mediamaps.ch/wiki/doku.php?id=geoinf14:postgis0
  2. Terminer l'exemple en exploitant le géoservice dans OpenLayers avec une ol.layer.Vector comme vu dans Ex5A.
geoinf17/geoservice0.txt · Last modified: 2018/05/16 10:05 (external edit)