diff --git a/GeoDa.cpp b/GeoDa.cpp
index e4d6690ba..1e8abcdeb 100644
--- a/GeoDa.cpp
+++ b/GeoDa.cpp
@@ -4256,20 +4256,23 @@ void GdaFrame::OnOpenBivariateLJC(wxCommandEvent& event)
     }
     
     // check if binary data
-    std::vector<double> data;
+    std::vector<double> data1, data2;
+    std::vector<bool> undef_data1, undef_data2;
     TableInterface* table_int = p->GetTableInt();
-    table_int->GetColData(VS.col_ids[0], VS.var_info[0].time, data);
-    for (int i=0; i<data.size(); i++) {
-        if (data[i] !=0 && data[i] != 1) {
+    table_int->GetColData(VS.col_ids[0], VS.var_info[0].time, data1);
+    table_int->GetColUndefined(VS.col_ids[0], VS.var_info[0].time, undef_data1);
+    for (int i=0; i<data1.size(); i++) {
+        if (data1[i] !=0 && data1[i] != 1) {
             wxString msg = _("Please select two binary variables for Bivariate Local Join Count.");
             wxMessageDialog dlg (this, msg, _("Warning"), wxOK | wxICON_WARNING);
             dlg.ShowModal();
             return;
         }
     }
-    table_int->GetColData(VS.col_ids[1], VS.var_info[1].time, data);
-    for (int i=0; i<data.size(); i++) {
-        if (data[i] !=0 && data[i] != 1) {
+    table_int->GetColData(VS.col_ids[1], VS.var_info[1].time, data2);
+    table_int->GetColUndefined(VS.col_ids[1], VS.var_info[1].time, undef_data2);
+    for (int i=0; i<data2.size(); i++) {
+        if (data2[i] !=0 && data2[i] != 1) {
             wxString msg = _("Please select two binary variables for Bivariate Local Join Count.");
             wxMessageDialog dlg (this, msg, _("Warning"), wxOK | wxICON_WARNING);
             dlg.ShowModal();
@@ -4277,6 +4280,35 @@ void GdaFrame::OnOpenBivariateLJC(wxCommandEvent& event)
         }
     }
     
+    // check if 2 variables has NO colocation
+    {
+        int num_obs = p->GetNumRecords();
+
+        vector<bool> undefs;
+        for (int i=0; i<num_obs; i++){
+            bool is_undef = undef_data1[i] || undef_data2[i];
+            undefs.push_back(is_undef);
+        }
+        
+        bool nocolocation = true;
+        
+        for (int i=0; i<num_obs; i++) {
+            if (undefs[i] == true) {
+                continue;
+            }
+            if (data1[i] == 1  && data2[i] == 1) {
+                nocolocation = false;
+                break;
+            }
+        }
+        
+        if (!nocolocation) {
+            wxMessageDialog dlg (this, _("Bivariate Join Count only applies to no co-location case. The selected variables have co-locations. Please change your selection, or use Co-location Join Count."), _("Error"), wxOK | wxICON_WARNING);
+            dlg.ShowModal();
+            return;
+        }
+    }
+    
 	JCCoordinator* lc = new JCCoordinator(w_id, p, VS.var_info, VS.col_ids);
     MLJCMapFrame *sf = new MLJCMapFrame(GdaFrame::gda_frame, p, lc, false);
 }
@@ -4329,7 +4361,7 @@ void GdaFrame::OnOpenMultiLJC(wxCommandEvent& event)
     }
     
     // check if more than 2 variables has colocation
-    if (num_vars > 2) {
+    if (num_vars >= 2) {
         std::vector<d_array_type> data(num_vars); // data[variable][time][obs]
         std::vector<b_array_type> undef_data(num_vars);
         for (int i=0; i<VS.var_info.size(); i++) {