Projected Geodata with a Bounding Box Brush

Aitoff projection with a brush that logs the bounding corners in latlong for the brush area.

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

.background {
  fill: #a4bac7;
}

.foreground {
  fill: none;
  stroke: #333;
  stroke-width: 1.5px;
}

.graticule {
  fill: none;
  stroke: #fff;
  stroke-width: .5px;
}

.graticule :nth-child(2n) {
  stroke-dasharray: 2,2;
}

.land {
  fill: #d7c7ad;
  stroke: #766951;
}

.boundary {
  fill: none;
  stroke: #a5967e;
}

.brush .extent {
  stroke: #fff;
  fill-opacity: .125;
  shape-rendering: crispEdges;
}

</style>
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script src="https://d3js.org/d3.geo.projection.v0.min.js"></script>
<script src="https://d3js.org/topojson.v0.min.js"></script>
<script>

var width = 960,
    height = 500;

var projection = d3.geo.aitoff();

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

var graticule = d3.geo.graticule();

var x = d3.scale.linear()
    .range([0, width]);

var y = d3.scale.linear()
    .range([height, 0]);

brush = d3.svg.brush()
    .x(x)
    .y(y)
    .on("brush", brushed)
    .on("brushend", bounding)
    .extent([[100, 100], [200, 200]]);

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

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

svg.append("use")
    .attr("class", "background")
    .attr("xlink:href", "#sphere");

svg.append("g")
    .attr("class", "graticule")
  .selectAll("path")
    .data(graticule.lines)
  .enter().append("path")
    .attr("d", path);

svg.append("use")
    .attr("class", "foreground")
    .attr("xlink:href", "#sphere");
    
    svg.append("g")
    .attr("class", "brush")
    .call(brush);

d3.json("/d/4090846/world-110m.json", function(error, world) {
  svg.insert("path", ".graticule")
      .datum(topojson.object(world, world.objects.land))
      .attr("class", "land")
      .attr("d", path);

svg.insert("path", ".graticule")
      .datum(topojson.mesh(world, world.objects.countries, function(a, b) { return a !== b; }))
      .attr("class", "boundary")
      .attr("d", path);

});

brushed();

function brushed() {

}

function bounding() {
  var extent = brush.extent();
  console.log("top left: " + projection.invert([x(extent[0][0]),y(extent[1][1])]))
  console.log("bottom right: " + projection.invert([x(extent[1][0]),y(extent[0][1])]))
}

</script>

Modified http://d3js.org/d3.v3.min.js to a secure url

Modified http://d3js.org/d3.geo.projection.v0.min.js to a secure url

Modified http://d3js.org/topojson.v0.min.js to a secure url

https://d3js.org/d3.v3.min.js

https://d3js.org/d3.geo.projection.v0.min.js

https://d3js.org/topojson.v0.min.js