AlbersUSA inverse proj parameters

This block to understand how the inverse AlbersUsa works, in answer to d3 issue #1984. In green, values that would work for Puerto Rico.

Forked from mbostock's block: AlbersUSA + PR

<!DOCTYPE html>
<meta charset="utf-8">
<style>

rect {
  fill: none;
  pointer-events: all;
}

.sphere {
  fill: none;
  stroke: #ccc;
  shape-rendering: crispEdges;
}

.graticule {
  fill: none;
  stroke: #777;
  stroke-opacity: .2;
}

.mesh {
  fill: none;
  stroke: #000;
}

</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>
<script src="albers-usa-pr.js"></script>
<script>

var width = 960,
    height = 500;

var projection = albersUsaPr()
    .scale(1070)
    .translate([width / 2, height / 2]);

var path = d3.geoPath()
    .projection(projection);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

var graticule = d3.geoGraticule()
    .step([2, 2]);

svg.append("rect")
    .attr("width", width)
    .attr("height", height);

svg.append("path")
    .datum({type: "Sphere"})
    .attr("class", "sphere")
    .attr("d", path);

svg.append("path")
    .datum(graticule)
    .attr("class", "graticule")
    .attr("d", path);

var k = projection.scale(), t = projection.translate();
svg.append('circle')
.attr('transform', 'translate(' + t + ')')
.attr('r', 5)
.attr('fill', 'red');

svg.selectAll('rect.bg')
.data( [ [[-.425,.120], [-.214,.234]], [[-.214,.166], [-.115,.234]], [[.32,.204], [.38,.234]],  ] )
.enter()
.append('rect')
.attr('class', 'bg')
.attr('x', function(d) { return t[0] + d[0][0] * k; })
.attr('y', function(d) { return t[1] + d[0][1] * k; })
.attr('width', function(d) { return (d[1][0] - d[0][0]) * k; })
.attr('height', function(d) { return (d[1][1] - d[0][1]) * k; })
.style('fill', 'rgba(255,200,200,.3)')

d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/us.json", function(error, us) {
  if (error) throw error;

svg.append("path")
      .datum(topojson.mesh(us))
      .attr("class", "mesh")
      .attr("d", path);
});

</script>

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

https://d3js.org/topojson.v2.min.js