1

I want to load and remove a layer in a specified interval of time. I make it blink with a random color function associate to my layer style. I can load this layer multiple times, unload it in a specified interval of time, but both actions at the same time failed (layer load and and load and load until Firefox crash). I also try clearLayer and setInterval(function() {getRandomColor();}, 200); without success.

How can I make my color function load in a specified interval of time ? (and make my style dynamic)

// Random colors
function getRandomColor() {
    var letters = '0123456789ABCDEF'.split('');
    var color = '#';
    for (var i = 0; i < 6; i++ ) {
        color += letters[Math.floor(Math.random() * 16)];
    }
return color;
}

// Layer style
function doStyleFields(feature) {
        return {
            color: '#000000',                   
            fillColor: getRandomColor(),
            weight: 0,
            dashArray: '',
            opacity: 1.0,
            fillOpacity: 0.5
        };
}

// Layer
function loadJson() {
    var exp_FieldsJSON = new L.geoJson(exp_Fields,{
        onEachFeature: pop_Fields,
        style: doStyleFields
    }).addTo(layerJson);
}

// LayerGroup
var layerJson = new L.LayerGroup();
var overlays = {"Fields": layerJson};   
L.control.layers(overlays).addTo(map);

// Interval
$(document).ready(function() {          
    setInterval(function() {loadJson();}, 200);         
    setInterval(function() {map.removeLayer(layerJson);}, 199); 
});
4

If my understanding is correct, in fact you remove and re-load your exp_Fields GeoJSON data into a new GeoJSON layer so that it comes with a new fill color?

In that case, why not simply changing the style of your GeoJSON layer, rather than remove and re-load? Use the setStyle() method.

Changes styles of GeoJSON vector layers with the given style function.

What may happen with your remove and re-load technique, is that because you have a slightly different interval (remove every 199 ms, re-load every 200 ms), your 2 intervals will become out-of-sync after 200 iterations (about 40 seconds).

Furthermore, in fact you just hide layerJson from map every 199 ms, but you add a new GeoJSON layer into layerJson every 200 ms, so they stack up and increase the required memory.

$(document).ready(function() {             
    setInterval(function() {
        // Could be directly applied to your GeoJSON layer if you kept a global reference to it.
        layerJson.eachLayer(function (layer) {
            layer.setStyle(doStyleFields);
        });
    }, 200);
});
  • It's better, thanks. My method wasn't good, you're right. A last issue : when I'm loading my document, i have to check the radio button to see the layer, how can i make it appear directely ? However my layer group is .addTo(Map) – GeoGyro Mar 9 '16 at 13:33
  • If you do a layerJson.addTo(map), your Layers Control should automatically select the corresponding radio. – ghybs Mar 9 '16 at 13:43
  • Glad it helped. Please can you mark the answer as "accepted" if it solved your issue, so that people know your question is resolved? – ghybs Mar 9 '16 at 13:54

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