Hello Stefano Cudini,
It seems that there is a bug with markers: they disappear on zoom in/out when falling out of zoom bounds, you have to uncheck/check the layer to get the markers back. I only noticed the issue once implemented locally, sigh... :)
Visible on your examples too if I except "Data by Callback".

The bug disappear if I set updateOutBounds to false.

Best regards and thank you for the script!

How can I add a custom icon using buildIcon? And why do the icons disappear when I define $data['icon']='myIcon'?

Using overpass API I want to see also a way using the center function:

L.layerJSON({url: 'http://overpass-api.de/api/interpreter?data=[out:json];(way({lat1},{lon1},{lat2},{lon2})[tourism=alpine_hut];);out center;',

        propertyItems: 'elements',
        propertyTitle: 'tags.name',
        propertyLoc: ['center.lat','center.lon'],

...

but it doesn't work

it produce an element Latlng (NaN,Nan)

Why?

Thanks in advanced
R

ps:

output json seems correct:
"version": 0.6,
"generator": "Overpass API",
"osm3s": {
"timestamp_osm_base": "2014-08-20T13:00:01Z",
"copyright": "The data included in this document is from www.openstreetmap.org. The data is made available under ODbL."
},
"elements": [
{
"type": "way",
"id": 103839515,
"center": {
"lat": 44.7271834,
"lon": 9.0168653
},
"nodes": [
1198725685,
1198724829,
1198725506,
1198725193,
1198725685
],
"tags": {
"building": "yes",
"name": "Bivacco Alda e Carla Merchesotti",
"operator": "Club Alpino Italiano - sezione di Novi Ligure",
"tourism": "alpine_hut"
}
},
{
"type": "way",
"id": 149158829,
"center": {
"lat": 44.4972211,
"lon": 8.4904252
},
"nodes": [
1621763986,
1621764012,
1621763996,
1621763974,
1621763987,
1621764003,
1621763986
],
"tags": {
"building": "yes",
"name": "Rifugio Sciverna",
"tourism": "alpine_hut",
"website": "http://www.rifugiosciverna.com"
}
},
{
"type": "way",
"id": 293034542,
"center": {
"lat": 44.7266464,
"lon": 9.1099179
},
"nodes": [
2965883248,
2965883247,
2965883250,
2965883253,
2965883252,
2965883251,
2965883248
],
"tags": {
"building": "yes",
"name": "Rifugio Piani di San Lorenzo",
"tourism": "alpine_hut"
}
}

]
}

Hi, @stefanocudini.

First, thank you for this very useful Leaflet plugin.

Leaflet Dynamic JSON Layer README's says:

callData alternative function that return data (if use $.ajax() set async=false)

This advice produces the expected result on callData(), which is to retrieve an arbitrary JSON from an arbitrary endpoint so L.layerJSON() render its markers correctly.

But according to XHR Living Standard:

Synchronous XMLHttpRequest outside of workers is in the process of being removed from the web platform as it has detrimental effects to the end user's experience. (This is a long process that takes many years.) Developers must not pass false for the async argument when entry settings object's global object is a Window object. User agents are strongly encouraged to warn about such usage in developer tools and may experiment with throwing an InvalidAccessError exception when it occurs.

This is exactly what modern browsers do. Take Chromium 53 for instance, when dynamically loading a JSON with jQuery.ajax(url, {async: false}), it throws at the console:

Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.

When async: true, there are no donuts for markers though. The data required isn't there yet when L.layerJSON() is fired, so it has nothing to show. In that case, the JSON data is loaded asynchronously at some arbitrary moment after window.onload().

We are still some years away from the day where this call is going to be promoted from a warning at the console to 'an InvalidAccessError exception'. So maybe the time to have a closer look into it has arrived.

Is there any possibility that you could improve callData() so it can deal with async: true?

I've got this error message in Chrome, using Leaflet v1.1.0:

Deprecated include of L.Mixin.Events: this property will be removed in future releases, please inherit from L.Evented instead. Error
at y (mydomain.com...)
at Function.v.extend (mydomain.com...)
at http://terkep.futonaptar.info/js/leaflet-layerjson.min.js:17:40
at http://terkep.futonaptar.info/js/leaflet-layerjson.min.js:17:5735

Is it possible to ugrade the plugin somehow?

Thanks in advance!

I have geojson that return polygons, like:

{ 
    "type": "FeatureCollection", 
    "features": [ 
        {
            "type": "Feature", 
            "geometry": {
                "type":"Polygon",
                "coordinates":[[[19.011786843804092,-33.653375433463729],[19.011769373600742,-33.653349976975719],[19.011758205302748,-33.653322172557736],[19.011753768101549,-33.653293088716289],[19.011756232516287,-33.653263843126368],[19.011765503840888,-33.653235559679977],[19.011781225783547,-33.653209325295592],[19.011802794158836,-33.653186148148144],[19.011829380106171,-33.653166918925265],[19.011859961942516,-33.653152376598015],[19.011893364425049,-33.653143080022403],[19.011928303915099,-33.653139386462314],[19.011963437707649,-33.653141437859937],[19.01199741563077,-33.653149155380788],[19.012028931931923,-33.653162242443429],[19.012056775457324,-33.65318019611707],[19.012079876195923,-33.653202326449289],[19.012218836195935,-33.65336531661319],[19.012236306399284,-33.653390773096675],[19.012247474697276,-33.653418577492495],[19.012251911898478,-33.653447661291523],[19.012249447483743,-33.653476906818987],[19.012240176159139,-33.65350519018606],[19.012224454216479,-33.653531424480278],[19.012202885841194,-33.653554601534722],[19.012176299893856,-33.653573830671014],[19.012145718057514,-33.65358837292704],[19.012112315574978,-33.653597669454541],[19.012077376084928,-33.653601362994955],[19.012042242292377,-33.653599311608303],[19.012008264369261,-33.653591594127811],[19.011976748068104,-33.653578507130455],[19.011948904542699,-33.653560553539918],[19.011925803804104,-33.653538423299807],[19.011786843804092,-33.653375433463729]]]
            }, 
            "properties": {
                "erven_id":"7141412",
                "ervenlines_id":"46784835"
            }
        }
    ]
}

I see in all your examples that you only work with points (markers). How will I handle Polygons, Multipolygons, LineStrings, MultiLineStrings, etc?

Hey Stefano, great script, works great with an external source. But how about a local file? When I manually download the file(json) from the api and store it locally I can't seem to load it using url or callData methods?
Thanks!

Hi there,

Im trying to pass some json however I am gtting the following error in my console
Uncaught SyntaxError: Unexpected token :

It's weird, above the console I am seeing the json result, however the makers are not drawing on the map. This is what Im using

var jsonLayer = new L.LayerJSON({
                        url: 'http://biocache.ala.org.au/ws/occurrences/search?q=genus:Macropus',
                        jsonpParam: 'json_callback',
                        propertyItems :'occurrences',
                        propertyLoc: ['decimalLatitude','decimalLongitude'],
                        propertyTitle: 'occurrences'
                    });
    map.addLayer(jsonLayer);

I'm not sure if Im doing something wrong or if its a plugin thing. Any suggestions?
Thanks,
Rowan

Hi Stefano

First of all, thank you for sharing your very useful plugins for leaflet.

I would like to know, if it's possible to get lines and polygons as a layer, when using leaflet-layerJSON?

I have tried the following script, but doesn't get any railways as a layer.

        var way = L.layerJSON({
            url: 'http://overpass-api.de/api/interpreter?data=[out:json];way({lat1},{lon1},{lat2},{lon2})[Key:railway];out;',
            propertyItems: 'elements',
            propertyTitle: 'tags.name',
            propertyLoc: ['lat','lon'],
            buildPopup: function(data, marker) {
                return data.tags.name || null;
            }
        }).addTo(map);

I'm new to coding and webmapping and apologize if my question is unclear or if it is posted in a wrong section.

Anders

Ciao Stefano,

I try to use your plugin to display the data from the UNHCR (Refugee Agency) with leaflet. They share the location of the displaced people around the world with an API in JSON here :

http://data.unhcr.org/wiki/index.php/Get-population-settlements

I took example on the Overpass API example you give here : http://labs.easyblog.it/maps/leaflet-layerjson/examples/overpass.html but so far I didn't manage to make it work.

I'm wondering if this is because of the syntax of the JSON. The Overpass API gives an JSON that looks like that :

{
"version": 0.6,
"generator": "Overpass API",
"osm3s": {
"timestamp_osm_base": "2014-11-12T14:32:02Z",
"copyright": "The data included in this document is from www.openstreetmap.org. The data is made available under ODbL."
},
"elements": [ ....

The UNHCR API JSON file directly starts with the data :

[
{
"name": "PTP Ref. Camp",
"country": "Liberia",
"region": "Grand Gedeh",
"population": [
{
"module_name": [
{
"EN": "Registered Refugee Population"
},
{
"FR": "Données démographiques concernant la population affectée"
}
],
"module_type": "Total Population & Demogrpahy",
"url": "http://data.unhcr.org/liberia/settlement.php?id=30&country=119&region=22",
"value": "15379",
"households": "5018",
"demography": {
"04M": "1276",
"04F": "1312",
"511M": "1847",
"511F": "1772",
"1217M": "1056",
"1217F": "826",
"1859M": "3293",
"1859F": "3459",
"60M": "220",
"60F": "318"
},
"updated_at": "2014-04-30 03:35:08"
}
],
"latitude": "6.067023000",
"longitude": "-8.139816000",
"instance_id": "liberia"
},

The code in the example you gave is :

var data = L.layerJSON({
url: 'http://overpass-api.de/api/interpreter?data=[out:json];node({lat1},{lon1},{lat2},{lon2})[amenity=bar];out;',
propertyItems: 'elements',
propertyTitle: 'tags.name',
propertyLoc: ['lat','lon'],
buildPopup: function(data, marker) {
return data.tags.name || null;
}
}).addTo(map)

I tried to adapt like this:

var sett = L.layerJSON({
url: 'http://data.unhcr.org/api/population/settlements.json',
propertyTitle: 'name',
propertyLoc: ['latitude','longitude'],
}
}).addTo(map);

But it doesn't work.

So my question:

Is it possible to use your plugin with a JSON file written like the UNHCR's one ? (without the "element" item ?)

Thank you in advance for your answer,

Cheers from France,

Leo

I have a layerJSON that users can remove and then re-add. The _markersCache persists so when it is re-added then none of the markers that existed are added to the map again.

https://github.com/stefanocudini/leaflet-layerJSON/blob/master/src/leaflet-layerjson.js#L219

When i tried turn off caching, markers and clusters are blinking. So i decided to set caching on true which seems to work fine on dragging but had an issue on Zoom Out event when is necessary to get new data.

it's caused from: clearLayers();
https://github.com/stefanocudini/leaflet-layerJSON/blob/master/src/leaflet-layerjson.js#L259