diff --git a/src/gis/tmeditmanager.cpp b/src/gis/tmeditmanager.cpp
index a641c8f8..c42b311f 100644
--- a/src/gis/tmeditmanager.cpp
+++ b/src/gis/tmeditmanager.cpp
@@ -2306,6 +2306,9 @@ bool tmEditManager::FlipLine() {
     for (unsigned int f = 0; f < mySelected->GetCount(); f++) {
         OGRFeature* myFeature = mySelLayer->GetFeatureByOID(mySelected->Item(f));
         wxASSERT(myFeature);
+        if (myFeature == nullptr) {
+            continue;
+        }
 
         // don't delete, internally geometry.
         OGRLineString* myOGRSelLine = (OGRLineString*)myFeature->GetGeometryRef();
diff --git a/src/gis/tmgisdatavector.cpp b/src/gis/tmgisdatavector.cpp
index e0437634..846df053 100644
--- a/src/gis/tmgisdatavector.cpp
+++ b/src/gis/tmgisdatavector.cpp
@@ -453,7 +453,9 @@ OGRGeometry* tmGISDataVector::CreateOGRGeometry(const wxRealPoint& pt) {
 bool tmGISDataVector::CutLineAtVertex(long oid, const wxRealPoint& clickedpt, int searchRadius, int layertype) {
     // get the line
     OGRFeature* myFeature = GetFeatureByOID(oid);
-    wxASSERT(myFeature);
+    if (myFeature == nullptr) {
+        return false;
+    }
     OGRLineString* myLine = (OGRLineString*)myFeature->GetGeometryRef();
 
     // create search buffer
diff --git a/src/gis/tmimport.cpp b/src/gis/tmimport.cpp
index 1bb65154..532080ed 100644
--- a/src/gis/tmimport.cpp
+++ b/src/gis/tmimport.cpp
@@ -228,6 +228,7 @@ bool tmImport::SetAttributes(DataBaseTM* database, PrjDefMemManage* prj, const w
                              wxArrayLong& oids) {
     // Get layer
     ProjectDefMemoryLayers* layer = prj->FindLayer(m_LayerName);
+    if (layer == nullptr) return false;
 
     // Get field names
     wxArrayString fields;
diff --git a/src/gis/tmimportgis.cpp b/src/gis/tmimportgis.cpp
index 8674de0b..814325ba 100644
--- a/src/gis/tmimportgis.cpp
+++ b/src/gis/tmimportgis.cpp
@@ -87,6 +87,11 @@ bool tmImportGIS::Import(DataBaseTM* database, PrjDefMemManage* prj, wxProgressD
         }
 
         OGRGeometry* myGeom = myFeature->GetGeometryRef();
+        if (myGeom == nullptr) {
+            OGRFeature::DestroyFeature(myFeature);
+            wxLogWarning(_("Empty geometry in feature %ld"), myFeature->GetFID());
+            continue;
+        }
         wxASSERT(myGeom);
         wxArrayLong oids;
 
diff --git a/src/gis/tmlayermanager.cpp b/src/gis/tmlayermanager.cpp
index 8aaa340b..375dc944 100644
--- a/src/gis/tmlayermanager.cpp
+++ b/src/gis/tmlayermanager.cpp
@@ -607,7 +607,11 @@ bool tmLayerManager::_ReplaceLayer(const wxFileName& filename, const wxString& o
     // need to create an attribut index ?
     if (myLayerToReplace->GetSymbolRuleManagerRef()->GetRulesRef()->GetCount() > 0 &&
         myLayerToReplace->GetSymbolRuleManagerRef()->IsUsingRules()) {
-        tmGISDataVectorSHP* myGISData = (tmGISDataVectorSHP*)tmGISData::LoadLayer(myLayerToReplace);
+        auto myGISData = (tmGISDataVectorSHP*)tmGISData::LoadLayer(myLayerToReplace);
+        if (myGISData == nullptr) {
+            wxLogError(_("Unable to load layer : %s"), myLayerToReplace->GetName().GetName());
+            return false;
+        }
         wxString myQuery2 = wxString::Format(_T("DROP INDEX on %s"), myLayerToReplace->GetName().GetName());
         myGISData->ExecuteSQLQuery(myQuery2);
         wxString myFieldName = myLayerToReplace->GetSymbolRuleManagerRef()->GetFieldName();