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Last active January 2, 2016 12:59
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Zoom based point clustering in CartoDB
Raw
index.html
<!DOCTYPE html>
<html>
<head>
<title>Leaflet multilayer example | CartoDB.js</title>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<link rel="shortcut icon" href="http://cartodb.com/assets/favicon.ico" />
<style>
html, body, #map {
height: 100%;
padding: 0;
margin: 0;
}
</style>
<link rel="stylesheet" href="http://libs.cartocdn.com/cartodb.js/v3/themes/css/cartodb.css" />
<!--[if lte IE 8]>
<link rel="stylesheet" href="http://libs.cartocdn.com/cartodb.js/v3/themes/css/cartodb.ie.css" />
<![endif]-->
</head>
<body>
<div id="map"></div>
<!-- include cartodb.js library -->
<script src="http://libs.cartocdn.com/cartodb.js/v3/cartodb.js"></script>
<script type="sql/html" id="sql_template">
WITH hgridA AS (SELECT CDB_HexagonGrid(ST_Expand(!bbox!, greatest(!pixel_width!,!pixel_height!) * 48), greatest(!pixel_width!,!pixel_height!) * 48) as cell),
bigs AS (SELECT * FROM (SELECT ST_Centroid(ST_Collect(i.the_geom_webmercator)) as the_geom_webmercator, count(i.cartodb_id) as points_count, 1 as cartodb_id, array_agg(cartodb_id) AS id_list FROM hgridA, (select * from tornados_copy) i where ST_Intersects(i.the_geom_webmercator, hgridA.cell) GROUP BY hgridA.cell) t WHERE points_count > 100 ),
hgridB AS (SELECT CDB_HexagonGrid(ST_Expand(!bbox!, greatest(!pixel_width!,!pixel_height!) * 36), greatest(!pixel_width!,!pixel_height!) * 36) as cell),
mids AS (SELECT * FROM (SELECT ST_Centroid(ST_Collect(i.the_geom_webmercator)) as the_geom_webmercator, count(i.cartodb_id) as points_count, 1 as cartodb_id, array_agg(cartodb_id) AS id_list FROM hgridB, (select * from tornados_copy) i where ST_Intersects(i.the_geom_webmercator, hgridB.cell) AND cartodb_id NOT IN (SELECT unnest(id_list) FROM bigs) GROUP BY hgridB.cell) t WHERE points_count > 25 ),
hgridC AS (SELECT CDB_HexagonGrid(ST_Expand(!bbox!, greatest(!pixel_width!,!pixel_height!) * 24), greatest(!pixel_width!,!pixel_height!) * 24) as cell),
smalls AS (SELECT * FROM (SELECT ST_Centroid(ST_Collect(i.the_geom_webmercator)) as the_geom_webmercator, count(i.cartodb_id) as points_count, 1 as cartodb_id, array_agg(cartodb_id) AS id_list FROM hgridC, (select * from tornados_copy) i where ST_Intersects(i.the_geom_webmercator, hgridC.cell) AND cartodb_id NOT IN (SELECT unnest(id_list) FROM bigs) AND cartodb_id NOT IN (SELECT unnest(id_list) FROM mids) GROUP BY hgridC.cell) t WHERE points_count > 5 )
SELECT the_geom_webmercator, 1 points_count, cartodb_id, ARRAY[cartodb_id], 'origin' as src FROM tornados_copy WHERE cartodb_id NOT IN (select unnest(id_list) FROM bigs) AND cartodb_id NOT IN (select unnest(id_list) FROM mids) AND cartodb_id NOT IN (select unnest(id_list) FROM smalls)
UNION ALL
SELECT *, 'bigs' as src FROM bigs
UNION ALL
SELECT *, 'mids' as src FROM mids
UNION ALL
SELECT *, 'smalls' as src FROM smalls
</script>
<script>
function main() {
// create leaflet map
var map = L.map('map', {
zoomControl: false,
center: [35, -85],
zoom: 6
})
// add a base layer
L.tileLayer('http://tile.stamen.com/toner/{z}/{x}/{y}.png', {
attribution: 'Stamen'
}).addTo(map);
var baseSql = $('#sql_template').html();
// add cartodb layer with one sublayer
cartodb.createLayer(map, {
user_name: 'andrew',
type: 'cartodb',
sublayers: [{
sql: baseSql,
cartocss: "#layer { text-size: 12; text-fill: red; text-name: [points_count]; text-face-name: 'DejaVu Sans Book'; text-halo-fill: #fff; text-halo-radius: 1; [src = 'mids'] {text-size: 36;} [src = 'smalls'] {text-size: 24; } [src = 'bigs'] { text-size: 48; } }"
}]
})
.addTo(map)
.done(function(layer) {
});
}
// you could use $(window).load(main);
window.onload = main;
</script>
</body>
</html>
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