D3 Block-a-Day: Day 15, January 15th, 2017

D3 Block-a-Day: Day 15, January, 15th 2017

New Year's Resolution for 2017: Make a D3 Block a day to teach myself D3. This is Number 15. This example builds on yesterday's scatterplot adding in a label indicating the year-to-year correlation. This correlation is supplied in the data set which is now JSON instead of csv (first try to use JSON data instead of a flat format like csv).

<!DOCTYPE html>
<meta charset="utf-8">
<head>
    <title>D3 Block-a-Day: Day 15, January 15, 2017</title>
</head>

.axis path,
	.axis line {
		 fill: none;
		 stroke: #000;
		 shape-rendering: crispEdges;
	}

.dot {
		stroke: black;
    stroke-width: 2px;
    fill: #ffe0e0;
	}

.tooltip {
  	background-color: #fff8dc;
  	padding: 7px;
  	text-shadow: #f5f5f5 0 1px 0;
  	font: 13px Helvetica Neue;
  	border: 2px solid;
  	border-color: black;
		border-radius: 5px;
  	position: absolute;
  	box-shadow: rgba(0, 0, 0, 0.3) 0 2px 10px;
  }
  
  .xaxis {
     font: 14px Helvetica Neue;
   }
  
   .yaxis {
     font: 14px Helvetica Neue;
   }
</style>
<body>
<script src="//d3js.org/d3.v4.min.js"></script>

/*
 * value accessor - returns the value to encode for a given data object.
 * scale - maps value to a visual display encoding, such as a pixel position.
 * map function - maps from data value to display value
 * axis - sets up axis
 */

// setup x
var xValue = function(d) { return d['YEAR_2015'];}, // data -> value
    xScale = d3.scaleLinear().range([0, width]), // value -> display
    xMap = function(d) { return xScale(xValue(d));}, // data -> display
    xAxis = d3.axisBottom(xScale);

// setup y
var yValue = function(d) { return d['YEAR_2016'];}, // data -> value
    yScale = d3.scaleLinear().range([height, 0]), // value -> display
    yMap = function(d) { return yScale(yValue(d));}, // data -> display
    yAxis = d3.axisLeft(yScale);

// add the graph canvas to the body of the webpage
var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

// add the tooltip area to the webpage
var tooltip = d3.select("body").append("div")
    .attr("class", "tooltip")
    .style("opacity", 0);

// load data
d3.json("baseball_team_data.json", function(error, data) {
			if (error) return console.warn(error);

// change string into number format
  data.forEach(function(d) {
    d['YEAR_2015'] = +d['YEAR_2015'];
    d['YEAR_2016'] = +d['YEAR_2016'];
  });

// don't want dots overlapping axis, so add in buffer to data domain
  xScale.domain([40, 120]);
  yScale.domain([40, 120]);

// x-axis
  svg.append("g")
      .attr("class", "xaxis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);
  
  svg.append("text")
   		.attr("transform",
            "translate(" + (width*0.1) + " ," +
                           (height + margin.top + 30) + ")")
      .style("text-anchor", "left")
      .style("font-family", "Helvetica Neue")
      .text("Wins 2015");

// y-axis
  svg.append("g")
      .attr("class", "yaxis")
      .call(yAxis);
  
  svg.append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 10 - margin.left)
  		.attr("x", - 0.75*height)
      .attr("dy", ".71em")
      .style("text-anchor", "middle")
      .style("font-family", "Helvetica Neue")
      .text("Wins 2016");

// draw dots
  svg.selectAll(".dot")
      .data(data)
	    .enter().append("circle")
      .attr("class", "dot")
      .attr("r", 10)
      .attr("cx", xMap)
      .attr("cy", yMap)
      .on("mouseover", function(d) {
          tooltip.transition()
               .duration(150)
          			.style("opacity", .9);
          tooltip.html("<b>" + d['TEAM'] + "</b>" + "<br/> 2015: " + xValue(d)
	        + " Wins, 2016: " + yValue(d) + " Wins")
               .style("left", (d3.event.pageX + 5) + "px")
               .style("top", (d3.event.pageY - 28) + "px");
      })
      .on("mouseout", function(d) {
          tooltip.transition()
               .duration(300)
               .style("opacity", 0);
      });
});

</script>
</body>

https://d3js.org/d3.v4.min.js