Render Custom Symbols for Bubble Layers
The Bubble Layer allows you to define the way symbols are rendered.
This approach works by defining a symbol function that uses the Drawing API to define the shape. The symbol is typically a Group of shapes.
The following example demonstrates how to render 200-kilometer lines in West-East direction as a symbol. Note that the lines get longer the farther you go North, which is due to that fact that the example uses the Mercator Projection.
<div id="map"></div>
<script>
var draw = kendo.dataviz.drawing;
var geom = kendo.dataviz.geometry;
$("#map").kendoMap({
center: [45, 45],
minZoom: 3,
zoom: 4,
wraparound: false,
layers: [{
type: "tile",
urlTemplate: "https://#= subdomain #.tile.openstreetmap.org/#= zoom #/#= x #/#= y #.png",
subdomains: ["a", "b", "c"],
attribution: "© <a href='https://osm.org/copyright'>OpenStreetMap contributors</a>"
}, {
type: "bubble",
attribution: "Population data from Nordpil and UN Population Division.",
dataSource: {
transport: {
read: {
url: "https://demos.telerik.com/kendo-ui/content/dataviz/map/urban-areas.json",
dataType: "json"
}
}
},
locationField: "Location",
valueField: "Pop2010",
symbol: function(e) {
var map = $("#map").data("kendoMap");
// Bubble location
var location = e.location;
// Find locations 100km west and east of center.
// https://docs.telerik.com/kendo-ui/api/javascript/dataviz/map/location/methods/destination
// Actual distance can be bound to e.dataItem fields
var l1 = location.destination(100000, 270);
var l2 = location.destination(100000, 90);
// View the (screen) coordinates for the locations.
// https://docs.telerik.com/kendo-ui/api/javascript/dataviz/ui/map/methods/locationToView
var p1 = map.locationToView(l1);
var p2 = map.locationToView(l2);
// Draw the lines.
// https://docs.telerik.com/kendo-ui/api/javascript/dataviz/drawing/circle
var path = new draw.Path({
stroke: {
width: 2,
color: "red"
}
});
path.moveTo(p1).lineTo(p2);
path.dataItem = e.dataItem;
return path;
}
}],
shapeClick: function(e) {
console.log(e);
}
});
</script>