diff --git a/js/tbl_gis_visualization.js b/js/tbl_gis_visualization.js
index 40dd9a0c80..cd7ed23358 100644
--- a/js/tbl_gis_visualization.js
+++ b/js/tbl_gis_visualization.js
@@ -14,8 +14,8 @@ var defaultX = 0;
 var defaultY = 0;
 
 // Variables
-var x;
-var y;
+var x = 0;
+var y = 0;
 var scale = 1;
 
 var svg;