Index: node_modules/d3-polygon/src/area.js
===================================================================
--- node_modules/d3-polygon/src/area.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-polygon/src/area.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,15 @@
+export default function(polygon) {
+  var i = -1,
+      n = polygon.length,
+      a,
+      b = polygon[n - 1],
+      area = 0;
+
+  while (++i < n) {
+    a = b;
+    b = polygon[i];
+    area += a[1] * b[0] - a[0] * b[1];
+  }
+
+  return area / 2;
+}
Index: node_modules/d3-polygon/src/centroid.js
===================================================================
--- node_modules/d3-polygon/src/centroid.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-polygon/src/centroid.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,20 @@
+export default function(polygon) {
+  var i = -1,
+      n = polygon.length,
+      x = 0,
+      y = 0,
+      a,
+      b = polygon[n - 1],
+      c,
+      k = 0;
+
+  while (++i < n) {
+    a = b;
+    b = polygon[i];
+    k += c = a[0] * b[1] - b[0] * a[1];
+    x += (a[0] + b[0]) * c;
+    y += (a[1] + b[1]) * c;
+  }
+
+  return k *= 3, [x / k, y / k];
+}
Index: node_modules/d3-polygon/src/contains.js
===================================================================
--- node_modules/d3-polygon/src/contains.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-polygon/src/contains.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,16 @@
+export default function(polygon, point) {
+  var n = polygon.length,
+      p = polygon[n - 1],
+      x = point[0], y = point[1],
+      x0 = p[0], y0 = p[1],
+      x1, y1,
+      inside = false;
+
+  for (var i = 0; i < n; ++i) {
+    p = polygon[i], x1 = p[0], y1 = p[1];
+    if (((y1 > y) !== (y0 > y)) && (x < (x0 - x1) * (y - y1) / (y0 - y1) + x1)) inside = !inside;
+    x0 = x1, y0 = y1;
+  }
+
+  return inside;
+}
Index: node_modules/d3-polygon/src/cross.js
===================================================================
--- node_modules/d3-polygon/src/cross.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-polygon/src/cross.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,7 @@
+// Returns the 2D cross product of AB and AC vectors, i.e., the z-component of
+// the 3D cross product in a quadrant I Cartesian coordinate system (+x is
+// right, +y is up). Returns a positive value if ABC is counter-clockwise,
+// negative if clockwise, and zero if the points are collinear.
+export default function(a, b, c) {
+  return (b[0] - a[0]) * (c[1] - a[1]) - (b[1] - a[1]) * (c[0] - a[0]);
+}
Index: node_modules/d3-polygon/src/hull.js
===================================================================
--- node_modules/d3-polygon/src/hull.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-polygon/src/hull.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,49 @@
+import cross from "./cross.js";
+
+function lexicographicOrder(a, b) {
+  return a[0] - b[0] || a[1] - b[1];
+}
+
+// Computes the upper convex hull per the monotone chain algorithm.
+// Assumes points.length >= 3, is sorted by x, unique in y.
+// Returns an array of indices into points in left-to-right order.
+function computeUpperHullIndexes(points) {
+  const n = points.length,
+      indexes = [0, 1];
+  let size = 2, i;
+
+  for (i = 2; i < n; ++i) {
+    while (size > 1 && cross(points[indexes[size - 2]], points[indexes[size - 1]], points[i]) <= 0) --size;
+    indexes[size++] = i;
+  }
+
+  return indexes.slice(0, size); // remove popped points
+}
+
+export default function(points) {
+  if ((n = points.length) < 3) return null;
+
+  var i,
+      n,
+      sortedPoints = new Array(n),
+      flippedPoints = new Array(n);
+
+  for (i = 0; i < n; ++i) sortedPoints[i] = [+points[i][0], +points[i][1], i];
+  sortedPoints.sort(lexicographicOrder);
+  for (i = 0; i < n; ++i) flippedPoints[i] = [sortedPoints[i][0], -sortedPoints[i][1]];
+
+  var upperIndexes = computeUpperHullIndexes(sortedPoints),
+      lowerIndexes = computeUpperHullIndexes(flippedPoints);
+
+  // Construct the hull polygon, removing possible duplicate endpoints.
+  var skipLeft = lowerIndexes[0] === upperIndexes[0],
+      skipRight = lowerIndexes[lowerIndexes.length - 1] === upperIndexes[upperIndexes.length - 1],
+      hull = [];
+
+  // Add upper hull in right-to-l order.
+  // Then add lower hull in left-to-right order.
+  for (i = upperIndexes.length - 1; i >= 0; --i) hull.push(points[sortedPoints[upperIndexes[i]][2]]);
+  for (i = +skipLeft; i < lowerIndexes.length - skipRight; ++i) hull.push(points[sortedPoints[lowerIndexes[i]][2]]);
+
+  return hull;
+}
Index: node_modules/d3-polygon/src/index.js
===================================================================
--- node_modules/d3-polygon/src/index.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-polygon/src/index.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,5 @@
+export {default as polygonArea} from "./area.js";
+export {default as polygonCentroid} from "./centroid.js";
+export {default as polygonHull} from "./hull.js";
+export {default as polygonContains} from "./contains.js";
+export {default as polygonLength} from "./length.js";
Index: node_modules/d3-polygon/src/length.js
===================================================================
--- node_modules/d3-polygon/src/length.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-polygon/src/length.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,23 @@
+export default function(polygon) {
+  var i = -1,
+      n = polygon.length,
+      b = polygon[n - 1],
+      xa,
+      ya,
+      xb = b[0],
+      yb = b[1],
+      perimeter = 0;
+
+  while (++i < n) {
+    xa = xb;
+    ya = yb;
+    b = polygon[i];
+    xb = b[0];
+    yb = b[1];
+    xa -= xb;
+    ya -= yb;
+    perimeter += Math.hypot(xa, ya);
+  }
+
+  return perimeter;
+}