Planets

Part answer to https://stackoverflow.com/questions/48620278/d3-js-radially-position-elements-around-an-object/

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

<body>
  <script>
    
    const radians = 0.0174532925

var center = {name: "sun", count: 20 }; //Will have more complex data in the future

var planets = [
    {name: "Mercury", count: 2},
    {name: "Venus", count: 3} ,
    {name: "Earth", count: 5},
    {name: "Mars", count: 4},
    {name: "Jupiter", count: 11},
    {name: "Saturn", count: 10},
    {name: "Uranus", count: 7},
    {name: "Neptune", count: 8} ];
    
 var w = 800, h = 800;

var svg = d3.select("body").append("svg")
    .attr("width", w)
    .attr("height", h);
    
 let orbitRadius = d3.scaleLinear()
  .domain([0,8]) //number of planets
  .range([90,w/2]) //you may need adjust this later
 
 let angle = d3.scaleLinear()
  .domain([0,9]) //number of planets + 1
  .range([0,360]) //you may need adjust this later

svg.selectAll("line")
    	.data(planets)
    	.enter()
    	.append("line")
    	.attr("x1", function(d,i){
       
       	let a = angle(i);
       	let r = orbitRadius(i);
       
       	return xCoord = x(a, r) + (w/2)
       
     })
    	.attr("y1", function(d,i){
       
       	let a = angle(i);
       	let r = orbitRadius(i);
       
        return yCoord = y(a, r) + (h/2)
       
     })
    	.attr("x2", (w/2))
    	.attr("y2", (h/2))
    	.style("stroke", "black")
    	.style("stroke-width", 2)
    
    
    
     var circleContainer = svg.selectAll("g mySolarText")
     .data(planets);

var circleContainerEnter = circleContainer.enter()
     .append("g")
     .attr("transform", function(d,i){
       
       	let a = angle(i);
       	let r = orbitRadius(i);
       
       	let xCoord = x(a, r) + (w/2)
        let yCoord = y(a, r) + (h/2)
       	
        return "translate("+ xCoord +"," + yCoord + ")"
     });

var circle = circleContainerEnter.append("circle")
      .attr("r", function(d){return d.count * 5} )
      .attr("cx", 0)
      .attr("cy", 0)
      .attr("stroke","black")
      .attr("fill", "white");

circleContainerEnter.append("text")
       .attr("dx", function(d){return -20})
       .text(function(d){
          return d.name}
        );
    
   function x (angle, radius) {
      // change to clockwise
      let a = 360 - angle
      // start from 12 o'clock
      return radius * Math.sin(a * radians)
    }

function y (angle, radius) {
      // change to clockwise
      let a = 360 - angle
      // start from 12 o'clock
      return radius * Math.cos(a * radians)
    }

</script>
</body>

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