I would like to filter the markers on my (geojson) layer according to two features: year and type of event, ideally using both filters (year and eventType) as check-boxes without using layerGroup at all. I would like to be able to click on a checkbox and update dynamically the markers by filtering them according to feature.properties.eventType
too, in addition to the year displayed, something like
<input type="checkbox" id="all" name="all" value="all">
<label for="all">All</label>
<input type="checkbox" id="funfair" name="funfair" value="newsletter">
<label for="funfair">Funfair</label>
<input type="checkbox" id="trade" name="trade" value="trade">
<label for="trade">Trade</label>
<input type="checkbox" id="exhibition" name="exhibition" value="exhibition">
<label for="exhibition">Paid exhibition</label>
etc… which would trigger a
filter: function(feature, layer) {
return feature.properties.eventType == value-of-checkbox;
}
I have five types of eventType. So, for instance, if 1890 is checked, the map is showing all 1890 events, no matter what kind of event it is (because by default it would show all events). If the user checks the 'funfair' and the 'trade' checkbox, though, I want the map to show only the 1890 events of the funfair and trade kind, and not other kind of events.
This is my complete script, which so far is working fine with filtering by year.
var oldmap = L.tileLayer('address', {
maxZoom: 12
}),
var modernmap = L.tileLayer('https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token={accessToken}', {
maxZoom: 12,
id: 'mapbox.streets',
accessToken: 'mytoken'
});
var map = L.map('map', {
center: [40.1857864,-4.5536861],
zoom: 7,
layers: [oldmap, modernmap]
});
var baseMaps = {
"Old map": oldmap,
"Modern map": modernmap
};
var jsontest = {"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [ -16.5471268,28.4136726 ]
},
"properties": {
"Name":"Point1",
"year":'1892',
"eventType":"funfair",
"notes":""
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [ 2.1753895,41.3767925 ]
},
"properties": {
"Name":"Point2",
"year":'1890',
"eventType":"trade demonstration",
"notes":""
}
}
]};
var mapLayerGroupsYear = [];
function onEachFeature(feature, layer) {
var year = mapLayerGroupsYear[feature.properties.year];
if (year === undefined) {
year = new L.layerGroup();
//add the layer to the map
year.addTo(map);
//store layer
mapLayerGroupsYear[feature.properties.year] = year;
}
//add the feature to the layer
year.addLayer(layer);
}
var myLayer = L.geoJSON(jsontest, {
onEachFeature: onEachFeature
})
L.control.layers(baseMaps, mapLayerGroupsYear).addTo(map);
I am a beginner with leaflet so please forgive the dumb question, in case it is.
Best Answer
I propose to have
<input>
checkboxes for both the years and the event types outside the map container. Thefilter
function in theL.GeoJson
definition rejects every feature that does not have both the respective checkboxes for its year and for its event type checked.Now every time the state of a checkbox changes, all markers are removed,
checkboxStates
is updated and then data is added again, going through the filter.The utility function
updateCheckboxStates
is here. It assumes that the<input>
elements have a class of eitherevent-type
oryear
.Here is a working jsfiddle: https://jsfiddle.net/newluck77/rk9v0uyo/
Edit: And three screenshots comparing behaviour:
All events
Trade demonstrations and events of 1892 excluded
Events of 1892 added again (trade demonstrations stay excluded)