diff --git a/src/js/portfolio.js b/src/js/portfolio.js
index ae04aa4..5d3eca3 100644
--- a/src/js/portfolio.js
+++ b/src/js/portfolio.js
@@ -26,20 +26,20 @@ function getNodeLabel(node){
   return label;
 }
 function getNodeYear(n){
-  if(typeof n['http://schema.org/dateCreated'] !== 'undefined') {
-    return n['http://schema.org/dateCreated'].substr(0,4);
+  if(typeof n['https://schema.org/dateCreated'] !== 'undefined') {
+    return n['https://schema.org/dateCreated'].substr(0,4);
   }
-  if(typeof n['http://schema.org/datePublished'] !== 'undefined') {
-    return n['http://schema.org/datePublished'].substr(0,4);
+  if(typeof n['https://schema.org/datePublished'] !== 'undefined') {
+    return n['https://schema.org/datePublished'].substr(0,4);
   }
-  if(typeof n['http://schema.org/startDate'] !== 'undefined') {
-    return n['http://schema.org/startDate'].substr(0,4);
+  if(typeof n['https://schema.org/startDate'] !== 'undefined') {
+    return n['https://schema.org/startDate'].substr(0,4);
   }
-  if(typeof n['http://schema.org/endDate'] !== 'undefined') {
-    return n['http://schema.org/endDate'].substr(0,4);
+  if(typeof n['https://schema.org/endDate'] !== 'undefined') {
+    return n['https://schema.org/endDate'].substr(0,4);
   }
-  if(typeof n['http://schema.org/foundingDate'] !== 'undefined') {
-    return n['http://schema.org/foundingDate'].substr(0,4);
+  if(typeof n['https://schema.org/foundingDate'] !== 'undefined') {
+    return n['https://schema.org/foundingDate'].substr(0,4);
   }
   return null;
 }
@@ -369,6 +369,7 @@ var positionNodesInCenter = function(idxs) {
 }
 var positionNodesInCircle = function(idxs, r) {
   let viewBox = getViewbox();
+  let zoom = getZoomValues();
   setViewboxForceCenter(); // sets forceCx & forceCy
   if(typeof r == 'undefined') {
     if(idxs.length == 1) {
@@ -378,8 +379,8 @@ var positionNodesInCircle = function(idxs, r) {
     }
   }
   currentNodePositionRadius = r;
-  let forceCx = viewBox[0] + viewBox[2]/2;
-  let forceCy = viewBox[1] + viewBox[3]/2;
+  let forceCx = viewBox[0] + viewBox[2]/2 - zoom['dx'];
+  let forceCy = viewBox[1] + viewBox[3]/2 - zoom['dy'];
 
   let stepSize = 2*Math.PI / idxs.length;
 
@@ -692,9 +693,29 @@ var deselectNode = function() {
 var forceCx, forceCy;
 var setViewboxForceCenter = function() {
   let viewBox = getViewbox();
-  forceCx = viewBox[0] + viewBox[2]/2;
-  forceCy = viewBox[1] + viewBox[3]/2;
+  let zoom = getZoomValues();
+  forceCx = viewBox[0] + viewBox[2]/2 - zoom['dx'];
+  forceCy = viewBox[1] + viewBox[3]/2 - zoom['dy'];
 }
+
+var getZoomValues = function(){
+  let zoomContainer = document.getElementById("container");
+  let dx = 0, dy = 0, scale = 1;
+  if(zoomContainer.transform.baseVal.length > 0) {
+      for(let transform of zoomContainer.transform.baseVal) {
+        if(transform.type == SVGTransform.SVG_TRANSFORM_TRANSLATE) {
+          dx += transform.matrix.e;
+          dy += transform.matrix.f;
+        }
+        else if (transform.type == SVGTransform.SVG_TRANSFORM_SCALE) {
+          scale *= transform.matrix.a; // assume simple scale
+        }
+      }
+  }
+
+  return {'dx': dx, 'dy': dy, 'scale': scale};
+}
+
 setViewboxForceCenter(); // sets forceCx & forceCy
 
 var graphInitialised = false;