<div dir="ltr"><div>this is the code of chatGPT with H3 :</div><div>backend :</div><div><br></div><div><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"><?php</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">header('Content-Type:
application/json');</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$pdo = new
PDO("pgsql:host=localhost;dbname=database", "user",
"password", [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$redis = new Redis();</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$redis->connect('127.0.0.1',
6379);</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$redis->auth('password');</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$shape = $_GET['shape'];</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$bbox = explode(',',
$_GET['bbox']);</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$size = $_GET['size'] ?? null;</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$radius = $_GET['radius'] ??
null;</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$resolution =
$_GET['resolution'] ?? 8;</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$cacheKey = "$shape:"
. implode('-', $bbox) . ":$size:$radius:$resolution";</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">if
($redis->exists($cacheKey)) {</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> echo $redis->get($cacheKey);</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> exit;</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">}</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">if ($shape ===
"hexagone") {</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> $sql = "</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> SELECT h3_geo_to_h3(ST_Y(geom),
ST_X(geom), :resolution) AS h3_cell, COUNT(*) AS point_count</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> FROM your_points_table</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> WHERE geom &&
ST_MakeEnvelope(:minLng, :minLat, :maxLng, :maxLat, 4326)</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> GROUP BY h3_cell;</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> ";</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> $params = [':resolution' => $resolution,
':minLng' => $bbox[0], ':minLat' => $bbox[1], ':maxLng' => $bbox[2],
':maxLat' => $bbox[3]];</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">} elseif ($shape ===
"cercle") {</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> $sql = "</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> SELECT
ST_AsGeoJSON(ST_Buffer(geom::geography, :radius)::geometry) AS shape, COUNT(*)
AS point_count</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> FROM your_points_table</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> WHERE geom &&
ST_MakeEnvelope(:minLng, :minLat, :maxLng, :maxLat, 4326)</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> GROUP BY shape;</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> ";</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> $params = [':radius' => $radius,
':minLng' => $bbox[0], ':minLat' => $bbox[1], ':maxLng' => $bbox[2],
':maxLat' => $bbox[3]];</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">} else {</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> $sql = "</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> SELECT
ST_AsGeoJSON(ST_Envelope(ST_Buffer(geom::geography, :size,
'quad_segs=1')::geometry)) AS shape, COUNT(*) AS point_count</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> FROM your_points_table</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> WHERE geom &&
ST_MakeEnvelope(:minLng, :minLat, :maxLng, :maxLat, 4326)</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> GROUP BY shape;</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> ";</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> $params = [':size' => $size, ':minLng'
=> $bbox[0], ':minLat' => $bbox[1], ':maxLng' => $bbox[2], ':maxLat'
=> $bbox[3]];</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">}</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$stmt = $pdo->prepare($sql);</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$stmt->execute($params);</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$result =
$stmt->fetchAll(PDO::FETCH_ASSOC);</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">$redis->setEx($cacheKey,
3600, json_encode($result));</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">echo json_encode($result);</span></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"><br></span></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">frontend :</span></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif"><br></span></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><!DOCTYPE html></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><html lang="fr"></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><head></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <meta
charset="UTF-8"></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
<title>Cartographie avec Forme Sélectionnée</title></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <link
rel="stylesheet"
href="<a href="https://unpkg.com/leaflet/dist/leaflet.css">https://unpkg.com/leaflet/dist/leaflet.css</a>"></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <script
src="<a href="https://unpkg.com/leaflet/dist/leaflet.js">https://unpkg.com/leaflet/dist/leaflet.js</a>"></script></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <script
src="<a href="https://code.jquery.com/jquery-3.6.0.min.js">https://code.jquery.com/jquery-3.6.0.min.js</a>"></script></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <style></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> #map { height:
500px; width: 100%; }</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </style></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"></head></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><body></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><h2>Choisissez la forme :</h2></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><select id="shapeSelector"></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <option
value="hexagone">Hexagone</option></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <option
value="cercle">Cercle</option></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> <option
value="carre">Carré</option></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"></select></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><div id="map"></div></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><script></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> const map =
L.map('map').setView([0, 0], 2);</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
L.tileLayer('https://{s}.<a href="http://tile.openstreetmap.org/{z}/{x}/{y}.png').addTo(map">tile.openstreetmap.org/{z}/{x}/{y}.png').addTo(map</a>);</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> let layer;</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> function
fetchData(shape) {</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> const bbox =
"-10,-10,10,10";</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> const url =
`backend.php?shape=${shape}&bbox=${bbox}&size=1000&radius=500&resolution=8`;</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> $.getJSON(url,
function (data) {</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> if (layer)
map.removeLayer(layer);</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> layer =
L.geoJSON(data, {</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> style:
{</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
color: shape === "carre" ? "green" : shape ===
"cercle" ? "blue" : "red",</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
weight: 2,</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
fillOpacity: 0.4</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> }</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
}).addTo(map);</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> });</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> }</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
$("#shapeSelector").change(function () {</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
fetchData($(this).val());</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> });</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif">
fetchData("hexagone"); // Chargement initial</p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"></script></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"> </p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"></body></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"><span style="font-size:12pt;line-height:107%;font-family:"Times New Roman",serif">
</span></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;line-height:107%;font-size:11pt;font-family:Aptos,sans-serif"></html></p></div><div><br></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div><div><div>Sylvain Ard<br>0549507724<br>0778380991</div><div><a href="mailto:sylvain.ard@gmail.com" target="_blank">sylvain.ard@gmail.com</a></div><div><a href="http://sylvain-ard.fr" target="_blank">https://www.sylvain-ard.fr</a><br></div>Entreprise individuelle SIRET : 80079243400022<br></div>Appt 26 Bât A Résidence Le Patio<br></div>83 rue de la Bugellerie<br></div>86000 Poitiers<br></div></div></div></div></div><br></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">Le ven. 14 mars 2025 à 20:49, Sylvain Ard <<a href="mailto:sylvain.ard@gmail.com">sylvain.ard@gmail.com</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>yes but H3 can't simplify the job ?</div><div><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div><div><div>Sylvain Ard<br>0549507724<br>0778380991</div><div><a href="mailto:sylvain.ard@gmail.com" target="_blank">sylvain.ard@gmail.com</a></div><div><a href="http://sylvain-ard.fr" target="_blank">https://www.sylvain-ard.fr</a><br></div>Entreprise individuelle SIRET : 80079243400022<br></div>Appt 26 Bât A Résidence Le Patio<br></div>83 rue de la Bugellerie<br></div>86000 Poitiers<br></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le ven. 14 mars 2025 à 20:48, Brent Wood <<a href="mailto:Brent.Wood@niwa.co.nz" target="_blank">Brent.Wood@niwa.co.nz</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>
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Hi,</div>
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Off the top of my head...</div>
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Postgis can easily cope with millions of records. Given the points are there, use that to create the hexagons as required - this can be done using
<a href="https://postgis.net/docs/ST_HexagonGrid.html" id="m_-7618079101520814894m_4221934677744483969LPlnk" target="_blank">https://postgis.net/docs/ST_HexagonGrid.html</a></div>
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<div>If you set up your QGIS project with preset zoom levels, and create a set of appropriately sized hexagons for each zoom level, then populate a column with the number of points it contains.</div>
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There will be some devilish details - as you zoom in, the polygon's real area will get smaller, so will contain less points. A fixed symbology will therefore change the colour range with the scale.</div>
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Calculating a normalised value, perhaps something like instead of the no of points, you calculate a normalised value - the hex at each scale with the most points gets 100, the rest get a value based on the no of points/the max for that scale, so all polygon
datasets will have colours set to values between 0 and 100. All doable with SQL.</div>
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Do all the data stuff in Postgis, then just plot in QGIS.</div>
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There are various ways to set QGIS up for this, but one reasonably straightforward way that should work is having a separate hexagon layer for each scale, with a scale limit on displaying it so that all map scales are represented by one of the hexagon layers,
with the fixed zoom levels/scales, set the same symbology for each layer, then group them into a single group.</div>
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Something to consider anyway...</div>
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Cheers</div>
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<div id="m_-7618079101520814894m_4221934677744483969Signature" style="color:inherit">
<div style="margin-right:0px;margin-left:0px;font-family:Calibri,Arial,Helvetica,sans-serif">
Brent Wood<br>
<br>
Principal Technician, Fisheries<br>
NIWA<br>
DDI: +64 (4) 3860529</div>
</div>
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<div id="m_-7618079101520814894m_4221934677744483969divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> QGIS-User <<a href="mailto:qgis-user-bounces@lists.osgeo.org" target="_blank">qgis-user-bounces@lists.osgeo.org</a>> on behalf of Sylvain Ard via QGIS-User <<a href="mailto:qgis-user@lists.osgeo.org" target="_blank">qgis-user@lists.osgeo.org</a>><br>
<b>Sent:</b> Friday, March 14, 2025 23:35<br>
<b>To:</b> <a href="mailto:qgis-user@lists.osgeo.org" target="_blank">qgis-user@lists.osgeo.org</a> <<a href="mailto:qgis-user@lists.osgeo.org" target="_blank">qgis-user@lists.osgeo.org</a>><br>
<b>Subject:</b> [Qgis-user] question</font>
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<div>Hello,<br>
I'd like a map with hexagons that are darker the more points there are underneath. My points are in a PostgreSQL table. If there are no points, there should be no hexagon. The hexagons have a constant size on the screen, so they have to be recalculated each
time the map is zoomed in. I want a truly optimized solution because I have millions of points. So, perhaps I could use QGIS-server.<br>
Please suggest a solution for both the server and client side.<br>
Best regards</div>
<div>PS : my map must be like GBIF maps</div>
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<div>Sylvain Ard<br>
0549507724<br>
0778380991</div>
<div><a href="mailto:sylvain.ard@gmail.com" target="_blank">sylvain.ard@gmail.com</a></div>
<div><a href="http://sylvain-ard.fr/" target="_blank">https://www.sylvain-ard.fr</a><br>
</div>
Entreprise individuelle SIRET : 80079243400022<br>
</div>
Appt 26 Bât A Résidence Le Patio<br>
</div>
83 rue de la Bugellerie<br>
</div>
86000 Poitiers<br>
</div>
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<tr><td><span>Brent Wood <br>
<font color="#1793d2">Principal Technician - GIS and Spatial Data Management</font><br>
<font color="#1793d2">Programme Leader - Environmental Information Delivery</font><br>
+64-4-386-0529<br>
<br>
National Institute of Water & Atmospheric Research Ltd (NIWA)<br>
301 Evans Bay Parade Hataitai Wellington New Zealand<br>
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