Decatur Townhouses Prices (1982-2018)

Decatur Townhouses prices gathered from the Dekalb County Tax Commissioner website. I've excluded gifts or inherited "sales" and some other outliers. There are obviously sales from before 1982, but at least online they don't give the actual values for those. Their records only go through 2018 right now. 2019 sales will be updated in 2020.

<!DOCTYPE html> 
<style> 
  
body {
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}

.title-text{
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.d3-tip {
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          transform: rotateY(20deg);
}
</style>

function median(values) {

values.sort( function(a,b) {return a - b;} );

var half = Math.floor(values.length/2);

if(values.length % 2)
        return values[half];
    else
        return (values[half-1] + values[half]) / 2.0;
}
  
  
function getMedians(d) {
  var medians = [];
  var years = {};
  for (i=0; i<d.length; i++) {
  	sale = d[i];
    year = sale.date.getFullYear();
    years[year] ? years[year].push(sale.close) : years[year] = [sale.close];
  }
  for (var year in years) {
    medians.push({date: new Date(year,6,1), close:median(years[year])});
  }
  return medians;
};
  
var tip = d3.tip()
	.attr('class', 'd3-tip')
  .offset([-10, 0])
	.html(function(d){
    return "<strong>Price: </strong>$" + numberWithCommas(d.close) + "</span><br/>Date: " + d.date.toDateString().substring(4) + "<br/>Unit: " + d.unit_letter + d.unit_number + "<br/>Deed Type: " + d.deed_type + "<br/>Sale Condition: " + d.sale_condition;
});
  
var median_tip = d3.tip()
	.attr('class', 'd3-tip')
  .offset([-10, 0])
	.html(function(d){
    return "<strong>Price: </strong>$" + numberWithCommas(d.close) + "</span><br/>Year: " + d.date.getFullYear();
});
  
var svg = d3.select("svg"),
    margin = {top: 70, right: 20, bottom: 30, left: 80},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom,
    g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");
g.call(tip);
g.call(median_tip);

var parseTime = d3.timeParse("%m/%d/%Y");

var dotSize = 2.5;
var selectedDotSize = 3.5;

var x = d3.scaleTime()
    .rangeRound([0, width]);

var y = d3.scaleLinear()
    .rangeRound([height, 0]);

var line = d3.line()
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.close); });
  
var ordinal = d3.scaleOrdinal()
  .domain(["Three Bedroom Units", "Two Bedroom Units"])
  .range([ "red", "steelblue"]);

var median_scale = d3.scaleOrdinal()
  .domain(["Three Bedroom Units", "Two Bedroom Units"])
  .range([ "orange", "green"]);

//x.domain(d3.extent(data, function(d) { return d.date; }));
  x.domain([new Date(1982,0,1), new Date(2018,11,31)]);
  y.domain([0, 400000]);
  
  g.append("g")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x))
    .select(".domain")
      .remove();

g.append("g")
  .attr("class", "legendOrdinal")
  .attr("transform", "translate(50,50)");

g.select(".legendOrdinal")
  .call(legendOrdinal);
  
  
 	individual_sales_title = "Individual Home Sales (1982-2018)";
  median_sales_title = "Annual Median Home Sales (1982-2018)";
  g.append("text")
  	.attr("class", "title-text")
  	.attr("x", width/2)
  	.style("text-anchor", "middle")
  	.text(individual_sales_title);

d3.select("body").append("div").attr("class", "tg-stuff").html(
  '<input class="tgl tgl-flip" id="cb5" type="checkbox" onclick="mediansOnly()"/><label class="tgl-btn" data-tg-off="View Annual Medians" data-tg-on="View Individual Sales" for="cb5"></label>'
  ); 
titleHeight = d3.select(".title-text").node().getBBox().height;
d3.select(".tg-stuff").style("left", width/2 + 'px').style("top", (margin.top + titleHeight) + 'px');   
  
  g.append("g")
      .call(d3.axisLeft(y))
    .append("text")
      .attr("fill", "#000")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("text-anchor", "end")
      .text("Price ($)");

g.append("path")
      .datum(two_bedroom_data)
 			.attr("class", "indiv-line")
      .attr("fill", "none")
  		.attr("data-legend", function(d){return 'Two Bedroom Units'})
      .attr("stroke", "steelblue")
      .attr("stroke-linejoin", "round")
      .attr("stroke-linecap", "round")
      .attr("stroke-width", 1.5)
      .attr("d", line);
  
  g.selectAll(".dot").data(two_bedroom_data).enter().append("circle")
   	.attr("class", "indiv-dots")
    .attr("r", dotSize)
  	.style("fill", "steelblue")
    .attr("cx", function(d) {return x(d.date);})
  	.attr("cy", function(d) {return y(d.close);})
  	.on('mouseover', function(d){
   		d3.select(this).style("r", selectedDotSize).style("fill", "black");
    	tip.show(d,this);
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  	.on("mouseout", function(d){
    	d3.select(this).style("r", dotSize).style("fill", "steelblue");
    	tip.hide(d, this);
  	});
  
  g.append("path")
      .datum(three_bedroom_data)
  		.attr("class", "indiv-line")
      .attr("fill", "none")
      .attr("stroke", "red")
      .attr("stroke-linejoin", "round")
      .attr("stroke-linecap", "round")
      .attr("stroke-width", 1.5)
      .attr("d", line);
  
  g.selectAll(".dot").data(three_bedroom_data).enter().append("circle")
  	.attr("class", "indiv-dots")
    .attr("r", dotSize).style("fill", "red")
    .attr("cx", function(d) {return x(d.date);})
  	.attr("cy", function(d) {return y(d.close);})
  	.on('mouseover', function(d){
   		d3.select(this).style("r", selectedDotSize).style("fill", "black");
    	tip.show(d,this);
  	})
  	.on("mouseout", function(d){
    	d3.select(this).style("r", dotSize).style("fill", "red");
    	tip.hide(d, this);
  	});

two_bedroom_medians = getMedians(two_bedroom_data);
  three_bedroom_medians = getMedians(three_bedroom_data);
  g.append("path")
      .datum(two_bedroom_medians)
  		.attr("class", "median-line")
  		.style("opacity", 0)
      .attr("fill", "none")
      .attr("stroke", "green")
      .attr("stroke-linejoin", "round")
      .attr("stroke-linecap", "round")
      .attr("stroke-width", 1.5)
      .attr("d", line);  
  
  g.append("path")
      .datum(three_bedroom_medians)
  		.attr("class", "median-line")
  		.style("opacity", 0)
      .attr("fill", "none")
      .attr("stroke", "orange")
      .attr("stroke-linejoin", "round")
      .attr("stroke-linecap", "round")
      .attr("stroke-width", 1.5)
      .attr("d", line);

g.selectAll(".dot").data(three_bedroom_medians).enter().append("circle")
    .attr("r", dotSize).style("fill", "orange")
  	.attr("class", "median-dots")
  	.style("opacity", 0)
  	.style("visibility", "hidden")
    .attr("cx", function(d) {return x(d.date);})
  	.attr("cy", function(d) {return y(d.close);})
  	.on('mouseover', function(d){
   		d3.select(this).style("r", selectedDotSize).style("fill", "black");
    	median_tip.show(d,this);
  	})
  	.on("mouseout", function(d){
    	d3.select(this).style("r", dotSize).style("fill", "orange");
    	median_tip.hide(d, this);
  	});
  
  g.selectAll(".dot").data(two_bedroom_medians).enter().append("circle")
    .attr("r", dotSize).style("fill", "green")
  	.attr("class", "median-dots")
  	.style("opacity", 0)
  	.style("visibility", "hidden")
    .attr("cx", function(d) {return x(d.date);})
  	.attr("cy", function(d) {return y(d.close);})
  	.on('mouseover', function(d){
   		d3.select(this).style("r", selectedDotSize).style("fill", "black");
    	median_tip.show(d,this);
  	})
  	.on("mouseout", function(d){
    	d3.select(this).style("r", dotSize).style("fill", "green");
    	median_tip.hide(d, this);
  	});
  
});

var showingMedians = false;
function mediansOnly(){

var svg = d3.select("body").transition().duration(500);

if (!showingMedians) {
    svg.select('.title-text').text(median_sales_title)
    svg.selectAll('.indiv-line').style("opacity", 0);
    svg.selectAll('.indiv-dots')
      .style("opacity", 0).transition()
      .style("visibility", "hidden");
    svg.selectAll('.median-line').style("opacity", 1);
    svg.selectAll('.median-dots')
      .style("opacity", 1)
    	.style("visibility", "visible");   
    
     
  legendOrdinal.scale(median_scale);
  g.select(".legendOrdinal").call(legendOrdinal); 
    
    showingMedians = true;
  } else {
    svg.select('.title-text').text(individual_sales_title)
    svg.selectAll('.indiv-line').style("opacity", 1);
    svg.selectAll('.indiv-dots')
      .style("opacity", 1)
      .style("visibility", "visible");
    svg.selectAll('.median-line').style("opacity", 0);
    svg.selectAll('.median-dots')
      .style("opacity", 0).transition()
      .style("visibility", "hidden");
    
    
  legendOrdinal.scale(ordinal);
  g.select(".legendOrdinal").call(legendOrdinal); 
    
    showingMedians = false;
  }

} 
</script>

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

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