function createViz() {
  d3.csv("test.csv",type, function (error, data) {
    if (error) throw error;

    dataViz(data)
  });
}

function dataViz(data) {

  //setup tooltip div & nav rect
  var tooltip = d3.select("#tooltip")
    .style("opacity", 0);

  // Parse the date / time
  var formatDate = d3.time.format("%d-%b"),
    formatMth = d3.time.format("%m-%d"),
    formatYear = d3.time.format("%Y");

  var bisect = d3.bisector(function(d) { return d.xPos; }).right;

  data.forEach(function(d,i) {
    d.xPos = formatMth(d.date);
  });

  var margin = {top: 5, right: 10, bottom: 5, left: 10},
    width = 960 - margin.left - margin.right,
    height = 100 - margin.top - margin.bottom;

  //this works as an x domain with range bands
  var x = d3.scale.ordinal().rangeRoundBands([0, width], 0.2);
  var y = d3.scale.linear().range([0,height]);

  var dataPerYear = d3.nest()
    .key(function(d) { return formatYear(d.date);})
    .entries(data);
  

  //x.domain(),needs to have "02-29" added manually
  //have tried this but it just gets added to the end
  //x.domain(data.map(function(d) { return d.xPos, "02-29"; }));
//  x.domain(data.map(function(d) { return d.xPos; }));
  var leapYearDays = [];// will be populated with all dates
  var currentDate = new Date(2016, 0, 1);// the date we'll be incrementing
  var safety = 0;// helps prevent infinite looping during development

  while(safety < 400 && currentDate.getFullYear() == 2016) {
    leapYearDays.push(formatMth(currentDate));
    currentDate.setDate(currentDate.getDate() + 1);
    safety++;
  }

  x.domain(leapYearDays.map(function(d) { return d; }));
  y.domain([0, d3.max(data, function(d) { return d.rain; })]);
  
  var svg = d3.select("#chart").selectAll("svg")
    .data(dataPerYear)
    .enter().append("svg")
    .attr("class", "charts")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

  svg.append("text")
    .attr("class", "year")
    .attr("transform", "rotate(-90)")
    .attr("y", 100)
    .attr("x",0 - (height / 2))
    .attr("dy", "1em")
    .style("text-anchor", "middle")
    .text(function(d) { return d.key; });

  svg.selectAll(".bar")
    .data(function(d) {return d.values;})
    .enter().append("rect")
    .attr("class", "bar")
    .attr("x", function(d) { return x(formatMth(d.date)); })
    .style("fill", function(d) { return d.date.getMonth() == 1 && d.date.getDate() == 29 ? "red" : null})
    .attr("y", 0)
    .attr("width", x.rangeBand())
    .attr("height", 0)
    .transition()
    .duration(1000)
    .ease("quad")
    .attr("height", function(d) { return y(d.rain); });
  
  var focus = svg.append("g");
    focus.style("display", "none");

  // append the rect at the intersection
  focus.append("rect")
    .attr("class", function(d) { return "y"+d.key; })
    .style("opacity", 0.5)
    .style("fill", "none")
    .attr("width", x.rangeBand())
    .attr("height", height);
  
  // append the rectangle to capture mouse
  svg.append("rect")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .attr("id", function(d,i) { return i; })
    .attr("chartID", function(d,i) { return i; })
    .attr("yearID", function(d) { return d.key; })
    .style("fill", "none")
    .style("pointer-events", "all")
    .on("mouseover", mouseover)
    .on("mouseout", mouseout)
    .on("mousemove", mousemove);

function mousemove() {
    //use this for inverting ordinal scale https://stackoverflow.com/questions/20758373/inversion-with-ordinal-scale (sepans in the comments)
    var chartID = d3.select(this);
    var keyID = chartID.attr("chartID");
    var yearID = chartID.attr("yearID");
    var id = document.getElementById(keyID);

    //for using getBoundingClientRect() http://help.dottoro.com/ljvmcrrn.php
    var yPosPerChart = parseInt(id.getBoundingClientRect().top+20);

    var domain = x.domain(),
      xpos = d3.mouse(this)[0],
      range = x.range();



    var x0 = domain[d3.bisect(range, xpos) - 1],
      i = bisect(dataPerYear[keyID].values, x0),
      d0 = dataPerYear[keyID].values[i - 1],
      d1 = dataPerYear[keyID].values[i];
      d = x0 - d0.date > d1.date - x0 ? d1 : d0;



    tooltip.transition()
      .duration(50)
      .style("opacity", .9);

    tooltip.html("<i>"+formatDate(d.date)+","+yearID+"</i><br>rainfall: "+d.rain+"mm")
      .style("left", (d3.event.pageX+20) + "px")
      .style("top", (d3.event.pageY+20) + "px");

    //detect yPos
      //.style("top", yPosPerChart + "px");


    focus.style("display", null);

    focus.select("rect.y"+yearID)
      .attr("transform",
      "translate(" + x(formatMth(d.date)) + ",0)")
      .style("fill", "pink");
  }

  function mouseover() {
    tooltip.style("opacity",.9);
  }

  function mouseout(){
    tooltip.style("opacity", 0);

    focus.select("rect")
      .style("fill", "none");

    focus.style("display", "none");

  }
 }

function type(d) {
  //var format = d3.time.format("%d-%b-%Y");
  var format = d3.time.format("%d-%b-%y");
  d.rain = +d.rain;
  d.date = format.parse(d.date);
  return d;
}