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Created December 20, 2016 16:36
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CARTO.js: using the SQL API to sum all the values of a column
Raw
index.html
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<style>html, body, #map { height: 100%; padding: 0; margin: 0 }</style>
<link rel="stylesheet" href="http://libs.cartocdn.com/cartodb.js/v3/3.15/themes/css/cartodb.css" />
<!-- include cartodb.js library -->
<script src="http://libs.cartocdn.com/cartodb.js/v3/3.15/cartodb.js"></script>
<style>
html, body, #map {
height: 100%;
padding: 0;
margin: 0;
}
#selector_menu{
position: absolute;
top: 20px;
left: 20px;
z-index: 9000;
}
/* set styles to the div element with id= box */
#box{
position: absolute;
top: 60px;
left: 20px;
width: 200px;
height: 170px;
opacity: 0.9;
padding: 5px 10px 5px 10px;
border-radius: 25px;
background-color: #FFF;
color: #fdb462;
}
/* set styles to the <h4> tag of the element with id= box */
#box h4{
font-style: italic;
}
/* set styles to the <p> tag of the element with id= box */
#box p{
text-align: center;
font-size: 18px;
color:red;
}
</style>
</head>
<body>
<div id="map"></div>
<div id='selector_menu'>
<select id='selector'>
<option value='no'>Without classification</option>
<option value='qua'>Quantile classification</option>
</select>
</div>
<div id ="box"><h4>Number of classes</h4><p id="num">None</p></div>
<script type="text/javascript">
var layer;
var vector = [];
var legend;
var sum = 0;
var val;
function main() {
var map = L.map('map', {
zoomControl: false,
center: [41.390205, 2.154007],
zoom: 12
});
// add basemap
L.tileLayer('http://{s}.basemaps.cartocdn.com/light_nolabels/{z}/{x}/{y}.png', {attribution: '&copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors, &copy; <a href="http://cartodb.com/attributions">CartoDB</a>'}).addTo(map);
cartodb.createLayer(map, {
user_name: 'oboix',
type: 'cartodb',
sublayers: [{
sql: "select * FROM barris_barcelona_test;",
cartocss: "#barris_barcelona_test{ polygon-fill: #FF6600;polygon-opacity: 1;line-color: #FFF;line-width: 0.5;line-opacity: 1; }",
}]
}).addTo(map)
.done(function(layer){
// start SQL API
var sql = new cartodb.SQL({ user: 'oboix'});
var LayerActions = {
no: function(){
sql.execute("SELECT * FROM barris_barcelona_test")
.done(function(data){
layer.setCartoCSS("#barris_barcelona_test{ polygon-fill: #FF6600;polygon-opacity: 1;line-color: #FFF;line-width: 0.5;line-opacity: 1; }");
});
},
qua: function(){
sql.execute("SELECT homes as homes FROM barris_barcelona_test")
.done(function(data){
for(i = 0; i < data.total_rows; i++){ // loop that reads each column of the table
val = data.rows[i].homes // stores value of the row in a javascript variable
sum = sum + val // does the sum
}
console.log(sum)
document.getElementById("num").innerHTML = sum;
var cssStyle = [
'#barris_barcelona_test{',
'polygon-fill: #FFEDA0;',
'polygon-opacity: 0.8;',
'line-color: #FFF;',
'line-width: 0.5;',
'line-opacity: 1;',
'}'
].join("\n");
layer.setCartoCSS(cssStyle);
});
return true;
}
}
$('#selector').change(function() {
LayerActions[$(this).val()]();
});
console.log(layer);
});
}
window.onload = main;
</script>
</body>
</html>
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