diff --git a/src/_umd_header.js b/src/_umd_header.js
index cf27df7..70ac706 100644
--- a/src/_umd_header.js
+++ b/src/_umd_header.js
@@ -1,6 +1,8 @@
 (function (root, factory) {
   if (typeof define === 'function' && define.amd) {
-    define(['d3', 'topojson'], factory);
+    define(['d3', 'topojson'], function(d3, topojson) {
+      return (root.planetaryjs = factory(d3, topojson, root));
+    });
   } else if (typeof exports === 'object') {
     module.exports = factory(require('d3'), require('topojson'));
   } else {