Voronoi binning experiments [UNLISTED]

Use Voronoi.find() to group data by the Voronoi cells of the top 10% data points.

Original work by Philippe Rivière for d3-voronoi (issue 17).

forked from Fil's block: Voronoi binning

<!DOCTYPE html>
<meta charset="utf-8">
<style>
circle {
  stroke: #444;
}
</style>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
 
var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height");

var color = d3.scaleOrdinal().range(d3.schemeCategory20);

var n = 400;
  
var data = d3.range(n)
    .map(function(d,i) { return [Math.random() * width, Math.random() * height, color(i), Math.random()]; });

var voronoi = d3.voronoi() 
    .size([width, height]);

var measures = [];

for(var bins=10; bins< 100; bins++) {

var sites = data.sort(function(a,b) {
  return d3.descending(a[3], b[3]);
})
.slice(0,bins);

var diagram = voronoi(sites);
diagram.find = find;

var totals = new Array(sites.length);

data.forEach(function(d){
    var found = diagram.find(d[0],d[1]);
  
  totals[found.index] = (totals[found.index] || 0) + d[3];

});

var mean = d3.mean(totals);
  var stddev = Math.sqrt( totals
                         .map(function(d) { return (d-mean)*(d-mean);})
                         .reduce (function(sum, value){return sum+value})
                         / totals.length);
  measures.push([totals.length, mean, stddev]);
  
  }

d3.select('svg')
.append('g')
.selectAll('circle')
.data(measures)
.enter()
.append('circle')
.attr('r', function(d) {return d[2];})
.attr('transform', function(d) { return 'translate('+ [ d[0]*6, d[2]*30 ] +')'; })
;
  
  
function find (x, y, radius){ 
  // optimization: start from most recent result  
  var i, next = diagram.find.found || Math.floor(Math.random() * diagram.cells.length);
  var cell = diagram.cells[next] || diagram.cells[next=0];
  var dx = x - cell.site[0], 
      dy = y - cell.site[1],
      dist = dx*dx + dy*dy;
  
 
  do { 
    cell = diagram.cells[i=next]; 
    next = null;
    cell.halfedges.forEach(function(e) {
      var edge = diagram.edges[e];
      var ea = edge.left;
      if (ea === cell.site || !ea) {
        ea = edge.right;
      }
      if (ea){
				var dx = x - ea[0],
            dy = y - ea[1],
            ndist = dx*dx + dy*dy;
        if (ndist < dist){
          dist = ndist;
          next = ea.index;
          return;
        }
      }
    });

} while (next !== null);

diagram.find.found = i;
  if (!radius || dist < radius * radius) return cell.site;
}

</script>

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