GeoHelm/app/get-json.php

58 lines
1.9 KiB
PHP

<?php
/*
* Title: PostGIS to GeoJSON
* Notes: Query a PostGIS table or view and return the results in GeoJSON format, suitable for use in OpenLayers, Leaflet, etc.
* Author: Bryan R. McBride, GISP
* Contact: bryanmcbride.com
* GitHub: https://github.com/bmcbride/PHP-Database-GeoJSON
*/
# Connect to PostgreSQL database
$conn = new PDO('pgsql:host=localhost;dbname=postgisftw','pgis','MYPGISPASSWORD');
# Build SQL SELECT statement and return the geometry as a GeoJSON element
$sql = "SELECT *, public.ST_AsGeoJSON(geom) AS geojson FROM countries WHERE continent = 'Europe'";
/*
* If bbox variable is set, only return records that are within the bounding box
* bbox should be a string in the form of 'southwest_lng,southwest_lat,northeast_lng,northeast_lat'
* Leaflet: map.getBounds().toBBoxString()
*/
if (isset($_GET['bbox'])) {
$bbox = explode(',', $_GET['bbox']);
$sql = $sql . ' WHERE public.ST_Transform(geom, 4326) && public.ST_SetSRID(public.ST_MakeBox2D(public.ST_Point('.$bbox[0].', '.$bbox[1].'), public.ST_Point('.$bbox[2].', '.$bbox[3].')),4326);';
}
# Try query or error
$rs = $conn->query($sql);
if (!$rs) {
echo 'An SQL error occured.\n';
exit;
}
# Build GeoJSON feature collection array
$geojson = array(
'type' => 'FeatureCollection',
'features' => array()
);
# Loop through rows to build feature arrays
while ($row = $rs->fetch(PDO::FETCH_ASSOC)) {
$properties = $row;
# Remove geojson and geometry fields from properties
unset($properties['geojson']);
unset($properties['geom']);
$feature = array(
'type' => 'Feature',
'geometry' => json_decode($row['geojson'], true),
'properties' => $properties
);
# Add feature arrays to feature collection array
array_push($geojson['features'], $feature);
}
header('Content-type: application/json');
echo json_encode($geojson, JSON_NUMERIC_CHECK);
$conn = NULL;
?>