diff --git a/files/www/cgi-bin/setup b/files/www/cgi-bin/setup
index 4d6b1b55..2c6d1ad7 100755
--- a/files/www/cgi-bin/setup
+++ b/files/www/cgi-bin/setup
@@ -793,7 +793,7 @@ html.print([[
     }).addTo(map);
 ]])
 
-if lat and lon then
+if type(lat) == "number" and type(lon) == "number" then
     html.print("marker= new L.marker([" .. lat .. "," .. lon .. "],{draggable: true, icon: dotIcon});")
     html.print("map.addLayer(marker);")
     html.print("map.setView([" .. lat .. "," .. lon .. "],13);")