text: d3.select("#geomap")
  .on("mousemove", function() {
      d3.select("#tooltip")
        .style("display", "block")
        .style("top", d3.event.pageY + 20 + "px")
        .style("left", d3.event.pageX + 20 + "px")
        .html("Welcome to the first chart!");
    })
    .on("mouseout", function() {
     d3.select("#tooltip")
       .style("display", "none");
   });
  