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rated 0 times [  35] [ 3]  / answers: 1 / hits: 18349  / 12 Years ago, thu, february 7, 2013, 12:00:00

Having the Leaflet Choropleth tutorial i have to emulate a click event on a specific map area. For example:
i have to have a function like clickOnMapItem(itemId) that will click on a map area which is defined by the following code



{type:Feature,id:05,properties:{name:Arkansas,density:56.43},geometry:{type:Polygon,coordinates:[...}


where id:05 is the id I need to click on



The rest of my code is as in the example:



state-data.js:



var statesData = {type:FeatureCollection,features:[
{type:Feature,id:01,properties:{name:Alabama,density:94.65},geometry:{type:Polygon,coordinates:[[[-87.359 and so on


html:



...header ommited



<!-- language:lang-html -->
<body>
<div id=map></div>

<script src=dist/leaflet.js></script>

<script type=text/javascript src=us-states.js></script>
<script type=text/javascript src=http://code.jquery.com/jquery-latest.min.js></script>
<script type=text/javascript>

var map = L.map('map').setView([37.8, -96], 4);

var cloudmade = L.tileLayer('http://{s}.tile.cloudmade.com/{key}/{styleId}/256/{z}/{x}/{y}.png', {
attribution: 'Map data &copy; 2011 OpenStreetMap contributors, Imagery &copy; 2011 CloudMade',
key: 'BC9A493B41014CAABB98F0471D759707',
styleId: 22677
}).addTo(map);


// control that shows state info on hover
var info = L.control();

info.onAdd = function (map) {
this._div = L.DomUtil.create('div', 'info');
this.update();
return this._div;
};

info.update = function (props) {
this._div.innerHTML = '<h4>US Population Density</h4>' + (props ?
'<b>' + props.name + '</b><br />' + props.density + ' people / mi<sup>2</sup>'
: 'Hover over a state');
};

info.addTo(map);


// get color depending on population density value
function getColor(d) {
return d > 1000 ? '#800026' :
d > 500 ? '#BD0026' :
d > 200 ? '#E31A1C' :
d > 100 ? '#FC4E2A' :
d > 50 ? '#FD8D3C' :
d > 20 ? '#FEB24C' :
d > 10 ? '#FED976' :
'#FFEDA0';
}

function style(feature) {
return {
weight: 2,
opacity: 1,
color: 'white',
dashArray: '3',
fillOpacity: 0.7,
fillColor: getColor(feature.properties.density)
};
}
//ON HOVER HANDLER
function highlightFeature(e) {
var layer = e.target;
layer.setStyle({
weight: 5,
color: '#666',
dashArray: '',
fillOpacity: 0.7
});

if (!L.Browser.ie && !L.Browser.opera) {
layer.bringToFront();
}

info.update(layer.feature.properties);
}

var geojson;

function resetHighlight(e) {
geojson.resetStyle(e.target);
info.update();
}

function zoomToFeature(e) {

map.fitBounds(e.target.getBounds());
}
//setting click handlers
function onEachFeature(feature, layer) {

layer.on({
mouseover: highlightFeature,
mouseout: resetHighlight,
click: zoomToFeature
});
}

geojson = L.geoJson(statesData, {
style: style,
onEachFeature: onEachFeature
}).addTo(map);

map.attributionControl.addAttribution('Population data &copy; <a href=http://census.gov/>US Census Bureau</a>');


var legend = L.control({position: 'bottomright'});

legend.onAdd = function (map) {

var div = L.DomUtil.create('div', 'info legend'),
grades = [0, 10, 20, 50, 100, 200, 500, 1000],
labels = [],
from, to;

for (var i = 0; i < grades.length; i++) {
from = grades[i];
to = grades[i + 1];

labels.push(
'<i style=background:' + getColor(from + 1) + '></i> ' +
from + (to ? '&ndash;' + to : '+'));
}

div.innerHTML = labels.join('<br>');
return div;
};

legend.addTo(map);


</script>
</body>


Thank you in advance!


More From » leaflet

 Answers
60

Sorry, it's a 3 years old question, but I will try to answer it here:



First, update your code below:



//setting click handlers
function onEachFeature(feature, layer) {
layer.on({
mouseover: highlightFeature,
mouseout: resetHighlight,
click: zoomToFeature
});
//add this line
layer._leaflet_id = feature.id;
}


The new line above will 'assign' your geoJSON's 'id' as your layer's leaflet_id,
then make a new function like this :



function clickOnMapItem(itemId) {
var id = parseInt(itemId);
//get target layer by it's id
var layer = geojson.getLayer(id);
//fire event 'click' on target layer
layer.fireEvent('click');
}


So, there's no need to populate any coordinate at all!!!



Hope it helps!


[#80369] Tuesday, February 5, 2013, 12 Years  [reply] [flag answer]
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marisela

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