dotsInvert.enter().append("circle")
      .attr("class", "vzb-al-dots-invert")
      .attr("r", 5)
      .on("mouseenter", (d, i) => {
        console.log("Point #" + i + ": " + d + " x=" + format(_this.xScale(d)) + " y=" + format(_this.yScale(d)));