Vega lite add an Interactive Point Highlight

Question

Could anyone helps me to add interactive highlight point on hover? I tried to add props from this example, but it did not work for me.

Here is my spec at Vega Lite Editor

Answer 1

The example is Vega-Lite but your spec is Vega. Try this - it gives a point and a tooltip for you.

{
  "description": "Total Count line chart.",
  "width": 1200,
  "height": 450,
  "padding": 5,
  "signals": [{"name": "interpolate", "value": "linear"}],
  "legends": [
    {
      "fill": "color",
      "orient": "bottom",
      "direction": "horizontal",
      "symbolType": "square"
    }
  ],
  "data": [
    {
      "name": "table",
      "values": [
        {"x": 0, "y": 145, "c": "All"},
        {"x": 1, "y": 153, "c": "All"},
        {"x": 2, "y": 280, "c": "All"},
        {"x": 3, "y": 150, "c": "All"},
        {"x": 4, "y": 280, "c": "All"},
        {"x": 5, "y": 140, "c": "All"},
        {"x": 6, "y": 90, "c": "All"},
        {"x": 0, "y": 30, "c": "Bulk carrier"},
        {"x": 1, "y": 20, "c": "Bulk carrier"},
        {"x": 2, "y": 90, "c": "Bulk carrier"},
        {"x": 3, "y": 60, "c": "Bulk carrier"},
        {"x": 4, "y": 50, "c": "Bulk carrier"},
        {"x": 5, "y": 40, "c": "Bulk carrier"},
        {"x": 6, "y": 10, "c": "Bulk carrier"},
        {"x": 0, "y": 50, "c": "Tanker ship"},
        {"x": 1, "y": 10, "c": "Tanker ship"},
        {"x": 2, "y": 50, "c": "Tanker ship"},
        {"x": 3, "y": 40, "c": "Tanker ship"},
        {"x": 4, "y": 110, "c": "Tanker ship"},
        {"x": 5, "y": 40, "c": "Tanker ship"},
        {"x": 6, "y": 20, "c": "Tanker ship"},
        {"x": 0, "y": 5, "c": "Dingy"},
        {"x": 1, "y": 23, "c": "Dingy"},
        {"x": 2, "y": 20, "c": "Dingy"},
        {"x": 3, "y": 0, "c": "Dingy"},
        {"x": 4, "y": 30, "c": "Dingy"},
        {"x": 5, "y": 20, "c": "Dingy"},
        {"x": 6, "y": 0, "c": "Dingy"},
        {"x": 0, "y": 50, "c": "Carrier ship"},
        {"x": 1, "y": 60, "c": "Carrier ship"},
        {"x": 2, "y": 90, "c": "Carrier ship"},
        {"x": 3, "y": 40, "c": "Carrier ship"},
        {"x": 4, "y": 50, "c": "Carrier ship"},
        {"x": 5, "y": 20, "c": "Carrier ship"},
        {"x": 6, "y": 40, "c": "Carrier ship"},
        {"x": 0, "y": 10, "c": "Other"},
        {"x": 1, "y": 40, "c": "Other"},
        {"x": 2, "y": 30, "c": "Other"},
        {"x": 3, "y": 10, "c": "Other"},
        {"x": 4, "y": 40, "c": "Other"},
        {"x": 5, "y": 20, "c": "Other"},
        {"x": 6, "y": 20, "c": "Other"}
      ]
    }
  ],
  "scales": [
    {
      "name": "x",
      "type": "point",
      "range": "width",
      "domain": {"data": "table", "field": "x"}
    },
    {
      "name": "y",
      "type": "linear",
      "range": "height",
      "nice": true,
      "zero": true,
      "domain": {"data": "table", "field": "y"}
    },
    {
      "name": "color",
      "type": "ordinal",
      "range": [
        "#61c7f7",
        "#BA20CE",
        "#60cf85",
        "#cd2c4f",
        "#ceae39",
        "#ffffff"
      ],
      "domain": {"data": "table", "field": "c"}
    }
  ],
  "axes": [
    {"orient": "bottom", "scale": "x"},
    {"orient": "left", "scale": "y"}
  ],
  "config": {
    "style": {
      "guide-label": {"fontSize": 14, "fill": "#cccccc", "fontWeight": 800}
    },
    "axis": {"grid": true, "gridColor": "#333333"}
  },
  "marks": [
    {
      "type": "group",
      "from": {"facet": {"name": "series", "data": "table", "groupby": "c"}},
      "marks": [
        {
          "type": "line",
          "from": {"data": "series"},
          "encode": {
            "enter": {
              "x": {"scale": "x", "field": "x"},
              "y": {"scale": "y", "field": "y"},
              "stroke": {"scale": "color", "field": "c"},
              "strokeWidth": {"value": 2}
            },
            "update": {
              "interpolate": {"signal": "interpolate"},
              "strokeOpacity": {"value": 1}
            },
            "hover": {"strokeOpacity": {"value": 0.5}}
          }
        },

        {
          "type": "symbol",
          "from": {"data": "series"},
          "encode": {
            "update": {
              "x": {"scale": "x", "field": "x"},
              "y": {"scale": "y", "field": "y"},
              "fillOpacity": {"value": 0}
            },
            
            "hover": {"fillOpacity": {"value": 1},
            "tooltip": {
                        "signal": "{'c':datum.c }"
                    }
            }
          }
        }
      ]
    }
  ]
}