source: Dev/trunk/d3/src/geo/bounds.js @ 76

/**
 * Given a GeoJSON object, returns the corresponding bounding box. The bounding
 * box is represented by a two-dimensional array: [[left, bottom], [right,
 * top]], where left is the minimum longitude, bottom is the minimum latitude,
 * right is maximum longitude, and top is the maximum latitude.
 */
d3.geo.bounds = function(feature) {
  var left = Infinity,
      bottom = Infinity,
      right = -Infinity,
      top = -Infinity;
  d3_geo_bounds(feature, function(x, y) {
    if (x < left) left = x;
    if (x > right) right = x;
    if (y < bottom) bottom = y;
    if (y > top) top = y;
  });
  return [[left, bottom], [right, top]];
};

function d3_geo_bounds(o, f) {
  if (o.type in d3_geo_boundsTypes) d3_geo_boundsTypes[o.type](o, f);
}

var d3_geo_boundsTypes = {
  Feature: d3_geo_boundsFeature,
  FeatureCollection: d3_geo_boundsFeatureCollection,
  LineString: d3_geo_boundsLineString,
  MultiLineString: d3_geo_boundsMultiLineString,
  MultiPoint: d3_geo_boundsLineString,
  MultiPolygon: d3_geo_boundsMultiPolygon,
  Point: d3_geo_boundsPoint,
  Polygon: d3_geo_boundsPolygon
};

function d3_geo_boundsFeature(o, f) {
  d3_geo_bounds(o.geometry, f);
}

function d3_geo_boundsFeatureCollection(o, f) {
  for (var a = o.features, i = 0, n = a.length; i < n; i++) {
    d3_geo_bounds(a[i].geometry, f);
  }
}

function d3_geo_boundsLineString(o, f) {
  for (var a = o.coordinates, i = 0, n = a.length; i < n; i++) {
    f.apply(null, a[i]);
  }
}

function d3_geo_boundsMultiLineString(o, f) {
  for (var a = o.coordinates, i = 0, n = a.length; i < n; i++) {
    for (var b = a[i], j = 0, m = b.length; j < m; j++) {
      f.apply(null, b[j]);
    }
  }
}

function d3_geo_boundsMultiPolygon(o, f) {
  for (var a = o.coordinates, i = 0, n = a.length; i < n; i++) {
    for (var b = a[i][0], j = 0, m = b.length; j < m; j++) {
      f.apply(null, b[j]);
    }
  }
}

function d3_geo_boundsPoint(o, f) {
  f.apply(null, o.coordinates);
}

function d3_geo_boundsPolygon(o, f) {
  for (var a = o.coordinates[0], i = 0, n = a.length; i < n; i++) {
    f.apply(null, a[i]);
  }
}