layerDefaults.shape.opacity Number (default: 1)

The the opacity of all shape layers.

Example - set tile layer default opacity

<div id="map"></div>
<script>
    $("#map").kendoMap({
        layerDefaults: {
            shape: {
                opacity: 0.5
            }
        },
        layers: [{
            type: "shape",
            dataSource: {
                type: "geojson",
                data: [{
                    "type": "Polygon",
                    "coordinates": [
                        [[30, 10], [40, 40], [20, 40], [10, 20], [30, 10]]
                    ]
                }]
            }
        }]
    });
</script>