Contents
How to draw markers in a GeoJSON leaflet?
By default simple markers are drawn for GeoJSON Points. We can alter this by passing a pointToLayer function in a GeoJSON options object when creating the GeoJSON layer. This function is passed a LatLng and should return an instance of ILayer, in this case likely a Marker or CircleMarker.
When to use the oneachfeature option in GeoJSON?
onEachFeature. The onEachFeature option is a function that gets called on each feature before adding it to a GeoJSON layer. A common reason to use this option is to attach a popup to features when they are clicked.
How are features and featurecollections used in GeoJSON?
Features in GeoJSON contain a Geometry object and additional properties, and a FeatureCollection contains a list of Features. Leaflet supports all of the GeoJSON types above, but Features and FeatureCollections work best as they allow you to describe features with a set of properties.
How are GeoJSON objects added to a map?
GeoJSON objects are added to the map through a GeoJSON layer. To create it and add it to a map, we can use the following code: GeoJSON objects may also be passed as an array of valid GeoJSON objects. Alternatively, we could create an empty GeoJSON layer and assign it to a variable so that we can add more features to it later.
How are points handled in a GeoJSON layer?
Points are handled differently than polylines and polygons. By default simple markers are drawn for GeoJSON Points. We can alter this by passing a pointToLayer function in a GeoJSON options object when creating the GeoJSON layer. This function is passed a LatLng and should return an instance of ILayer, in this case likely a Marker or CircleMarker.
How does the pointtolayer function work in GeoJSON?
The function will then pass a Lat/Lng allowing us to extend our GeoJSON styling options. To do so, we’ll call the pointToLayer function. Since we’re dealing with points, we can return L.CircleMarker ( L.Marker also works). From there we can set our parameters. In this case a circle radius of 10 pixels and fill opacity of 85% was set.
How do you control visibility in GeoJSON layer?
To accomplish this we pass a function as the filter option. This function gets called for each feature in your GeoJSON layer, and gets passed the feature and the layer. You can then utilise the values in the feature’s properties to control the visibility by returning true or false.