Ellipse d3js

<!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; }
    .ellipse-bg { fill: none; stroke:#000;stroke-width:1px}
    .ellipse-data { fill: green; stroke: none;}
  </style>
</head>

<body>
  
  <script>
    var svg = d3.select("body").append("svg")
      .attr("width", 960)
      .attr("height", 500)
		
    let minMax = [1, 10]
    let scaleX = d3.scaleLinear().domain(minMax).range([10, 50])
    let scaleY = d3.scaleLinear().domain(minMax).range([8, 25])
    
    console.log(scaleX(10))
    svg.append("ellipse")
      .attr("cx", 150)
      .attr("cy", 100)
      .attr("rx", 50)
			.attr("ry", 25)
      .attr("class", "ellipse-bg")
    
    let n = 5
    svg.append("ellipse")
      .attr("cx", 150 + scaleX.range()[1] - scaleX(n))
      .attr("cy", 100)
      .attr("rx", scaleX(n))
			.attr("ry", scaleY(n))
      .attr("class", "ellipse-data")
     
  </script>
</body>

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