diff --git a/CMakeLists.txt b/CMakeLists.txt
index bb161cf0..eb99bedf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -129,9 +129,9 @@ endif (CGAL_FOUND)
 
 # check required dependencies
 find_package(Boost COMPONENTS system thread REQUIRED)
-find_package(ZLIB 1.2.9 REQUIRED)
+find_package(ZLIB 1.2.11 REQUIRED)
 find_package(Threads REQUIRED)
-find_package(SimGear 2020.1.0 REQUIRED)
+find_package(SimGear 2020.3.0 REQUIRED)
 find_package(GDAL 2.0.0 REQUIRED)
 find_package(TIFF REQUIRED) # needed for SRTM
 
diff --git a/src/Airports/CMakeLists.txt b/src/Airports/CMakeLists.txt
index a0273294..2b9afced 100644
--- a/src/Airports/CMakeLists.txt
+++ b/src/Airports/CMakeLists.txt
@@ -1 +1 @@
-add_subdirectory(GenAirports850)
+add_subdirectory(GenAirports)
diff --git a/src/Airports/GenAirports850/CMakeLists.txt b/src/Airports/GenAirports/CMakeLists.txt
similarity index 89%
rename from src/Airports/GenAirports850/CMakeLists.txt
rename to src/Airports/GenAirports/CMakeLists.txt
index 258c69c9..e104ce9b 100644
--- a/src/Airports/GenAirports850/CMakeLists.txt
+++ b/src/Airports/GenAirports/CMakeLists.txt
@@ -2,7 +2,7 @@ include_directories(${GDAL_INCLUDE_DIR})
 include_directories(${PROJECT_SOURCE_DIR}/src/Lib)
 include_directories(${PROJECT_SOURCE_DIR}/src/Lib/terragear)
 
-add_executable(genapts850
+add_executable(genapts
     airport.hxx airport.cxx
     apt_math.hxx apt_math.cxx
     beznode.hxx
@@ -26,7 +26,7 @@ add_executable(genapts850
     trafficFlow.cxx trafficFlow.hxx
 )
 
-target_link_libraries(genapts850
+target_link_libraries(genapts
     terragear
     Array
     ${GDAL_LIBRARY}
@@ -36,4 +36,4 @@ target_link_libraries(genapts850
     ${SIMGEAR_CORE_LIBRARY_DEPENDENCIES}
     ${Boost_LIBRARIES})
 
-install(TARGETS genapts850 RUNTIME DESTINATION bin)
+install(TARGETS genapts RUNTIME DESTINATION bin)
diff --git a/src/Airports/GenAirports850/airport.cxx b/src/Airports/GenAirports/airport.cxx
similarity index 82%
rename from src/Airports/GenAirports850/airport.cxx
rename to src/Airports/GenAirports/airport.cxx
index b81e3e7b..8b28d998 100644
--- a/src/Airports/GenAirports850/airport.cxx
+++ b/src/Airports/GenAirports/airport.cxx
@@ -214,16 +214,18 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
 
     // Find the average of all the runway and heliport long / lats
     int num_samples = 0;
-    for (unsigned int i = 0; i < runways.size(); i++) {
-        apt_lon += runways[i]->GetMidpoint().getLongitudeDeg();
-        apt_lat += runways[i]->GetMidpoint().getLatitudeDeg();
+    for (auto& runway : runways) {
+        apt_lon += runway->GetMidpoint().getLongitudeDeg();
+        apt_lat += runway->GetMidpoint().getLatitudeDeg();
         num_samples++;
     }
-    for (unsigned int i = 0; i < helipads.size(); i++) {
-        apt_lon += helipads[i]->GetLoc().getLongitudeDeg();
-        apt_lat += helipads[i]->GetLoc().getLatitudeDeg();
+
+    for (auto& helipad : helipads) {
+        apt_lon += helipad->GetLoc().getLongitudeDeg();
+        apt_lat += helipad->GetLoc().getLatitudeDeg();
         num_samples++;
     }
+
     apt_lon = apt_lon / (double)num_samples;
     apt_lat = apt_lat / (double)num_samples;
 
@@ -232,8 +234,8 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
 
     // If we are cutting in the linear features, add them first
     if (pavements.size()) {
-        for (unsigned int i = 0; i < pavements.size(); i++) {
-            AddFeatures(pavements[i]->GetFeatures());
+        for (auto& pavement : pavements) {
+            AddFeatures(pavement->GetFeatures());
         }
     }
 
@@ -247,15 +249,14 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
         tgAccumulator lf_accum(icao);
 
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << features.size() << " Linear Feature Polys");
-        for (unsigned int i = 0; i < features.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Feature Poly " << i + 1 << " of " << features.size() << " : " << features[i]->GetDescription());
+        unsigned i = 0;
+        for (auto& feature : features) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Feature Poly " << ++i << " of " << features.size() << " : " << feature->GetDescription());
 
             bool make_shapefiles = false;
-            features[i]->BuildBtg(line_polys, rwy_lights, lf_accum, make_shapefiles);
+            feature->BuildBtg(line_polys, rwy_lights, lf_accum, make_shapefiles);
         }
 
-        //        lf_accum.ToShapefiles( "./lf_accum", "test", false );
-
         log_time = time(0);
         TG_LOG(SG_GENERAL, SG_ALERT, "Finished building Linear Features for " << icao << " at " << DebugTimeToString(log_time));
     }
@@ -266,25 +267,21 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
     // Build runways next
     if (runways.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << runways.size() << " Runway Polys");
-        for (unsigned int i = 0; i < runways.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Runway " << i + 1 << " of " << runways.size());
-            //slivers.clear();
+        unsigned i = 0;
+        for (auto& runway : runways) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Runway " << i+1 << " of " << runways.size());
 
-            if (isDebugRunway(i)) {
+            if (isDebugRunway(i))
                 sprintf(shapefile_name, "runway_%u", i);
-            } else {
+            else
                 strcpy(shapefile_name, "");
-            }
             shapefile = shapefile_name;
 
-            if (boundary.size()) {
-                runways[i]->BuildBtg(rwy_polys, rwy_lights, slivers, pvmt_accum, shapefile);
-            } else {
-                runways[i]->BuildBtg(rwy_polys, rwy_lights, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum, shapefile);
-            }
-
-            // Now try to merge any slivers we found
-            // tgPolygon::MergeSlivers( rwy_polys, slivers );
+            if (boundary.size())
+                runway->BuildBtg(rwy_polys, rwy_lights, slivers, pvmt_accum, shapefile);
+            else
+                runway->BuildBtg(rwy_polys, rwy_lights, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum, shapefile);
+            ++i;
         }
 
         log_time = time(0);
@@ -293,53 +290,45 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
 
     if (lightobjects.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << lightobjects.size() << " Light Objects ");
-        for (unsigned int i = 0; i < lightobjects.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build runway light " << i + 1 << " of " << lightobjects.size());
-            lightobjects[i]->BuildBtg(rwy_lights);
+        unsigned i = 0;
+        for (auto& light : lightobjects) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build runway light " << ++i << " of " << lightobjects.size());
+            light->BuildBtg(rwy_lights);
         }
     }
 
     // Build helipads (use runway poly- and texture list for this)
     if (helipads.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << helipads.size() << " Helipad Polys ");
-        for (unsigned int i = 0; i < helipads.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build helipad " << i + 1 << " of " << helipads.size());
-            //slivers.clear();
+        unsigned i = 0;
+        for (auto& helipad : helipads) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build helipad " << ++i << " of " << helipads.size());
 
-            if (boundary.size()) {
-                helipads[i]->BuildBtg(rwy_polys, rwy_lights, slivers, pvmt_accum);
-            } else {
-                helipads[i]->BuildBtg(rwy_polys, rwy_lights, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum);
-            }
-
-            // Now try to merge any slivers we found
-            //tgPolygon::MergeSlivers( rwy_polys, slivers );
+            if (boundary.size())
+                helipad->BuildBtg(rwy_polys, rwy_lights, slivers, pvmt_accum);
+            else
+                helipad->BuildBtg(rwy_polys, rwy_lights, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum);
         }
     }
 
     // Build the pavements
     if (pavements.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << pavements.size() << " Pavement Polys ");
-        for (unsigned int i = 0; i < pavements.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Pavement " << i + 1 << " of " << pavements.size() << " : " << pavements[i]->GetDescription());
-            //slivers.clear();
+        unsigned i = 0;
+        for (auto& pavement : pavements) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Pavement " << i+1 << " of " << pavements.size() << " : " << pavement->GetDescription());
 
-            if (isDebugPavement(i)) {
+            if (isDebugPavement(i))
                 sprintf(shapefile_name, "pvmnt_%u", i);
-            } else {
+            else
                 strcpy(shapefile_name, "");
-            }
             shapefile = shapefile_name;
 
-            if (boundary.size()) {
-                pavements[i]->BuildBtg(pvmt_polys, slivers, pvmt_accum, shapefile);
-            } else {
-                pavements[i]->BuildBtg(pvmt_polys, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum, shapefile);
-            }
-
-            // Now try to merge any slivers we found
-            //tgPolygon::MergeSlivers( rwy_polys, slivers );
-            //tgPolygon::MergeSlivers( pvmt_polys, slivers );
+            if (boundary.size())
+                pavement->BuildBtg(pvmt_polys, slivers, pvmt_accum, shapefile);
+            else
+                pavement->BuildBtg(pvmt_polys, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum, shapefile);
+            ++i;
         }
 
         log_time = time(0);
@@ -349,60 +338,48 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
     // Build the legacy taxiways
     if (taxiways.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << taxiways.size() << " Taxiway Polys ");
-        for (unsigned int i = 0; i < taxiways.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Taxiway " << i + 1 << " of " << taxiways.size());
-            //slivers.clear();
 
-            if (isDebugTaxiway(i)) {
+        unsigned i = 0;
+        for (auto& taxiway : taxiways) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Taxiway " << i+1 << " of " << taxiways.size());
+
+            if (isDebugTaxiway(i))
                 sprintf(shapefile_name, "taxiway_%u", i);
-            } else {
+            else
                 strcpy(shapefile_name, "");
-            }
             shapefile = shapefile_name;
 
-            if (boundary.size()) {
-                taxiways[i]->BuildBtg(pvmt_polys, rwy_lights, slivers, pvmt_accum, shapefile);
-            } else {
-                taxiways[i]->BuildBtg(pvmt_polys, rwy_lights, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum, shapefile);
-            }
-
-            // Now try to merge any slivers we found
-            //tgPolygon::MergeSlivers( rwy_polys, slivers );
-            //tgPolygon::MergeSlivers( pvmt_polys, slivers );
+            if (boundary.size())
+                taxiway->BuildBtg(pvmt_polys, rwy_lights, slivers, pvmt_accum, shapefile);
+            else
+                taxiway->BuildBtg(pvmt_polys, rwy_lights, slivers, apt_base_polys, apt_clearing_polys, pvmt_accum, shapefile);
+            ++i;
         }
     }
 
     // Build runway shoulders here
     if (runways.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << runways.size() << " Runway Shoulder Polys ");
-        for (unsigned int i = 0; i < runways.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Runway shoulder " << i + 1 << " of " << runways.size());
 
-            if (runways[i]->GetsShoulder()) {
-                //slivers.clear();
-                runways[i]->BuildShoulder(rwy_polys, slivers, pvmt_accum);
+        unsigned i = 0;
+        for (auto& runway : runways) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Runway shoulder " << ++i << " of " << runways.size());
 
-                // Now try to merge any slivers we found
-                //tgPolygon::MergeSlivers( rwy_polys, slivers );
-                //tgPolygon::MergeSlivers( pvmt_polys, slivers );
-            }
+            if (runway->GetsShoulder())
+                runway->BuildShoulder(rwy_polys, slivers, pvmt_accum);
         }
     }
 
     // Build helipad shoulders here
     if (helipads.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << runways.size() << " Helipad Shoulder Polys ");
-        for (unsigned int i = 0; i < helipads.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Helipad shoulder " << i + 1 << " of " << helipads.size());
 
-            if (helipads[i]->GetsShoulder()) {
-                //slivers.clear();
-                helipads[i]->BuildShoulder(rwy_polys, slivers, pvmt_accum);
+        unsigned i = 0;
+        for (auto& helipad : helipads) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build Helipad shoulder " << ++i << " of " << helipads.size());
 
-                // Now try to merge any slivers we found
-                //tgPolygon::MergeSlivers( rwy_polys, slivers );
-                //tgPolygon::MergeSlivers( pvmt_polys, slivers );
-            }
+            if (helipad->GetsShoulder())
+                helipad->BuildShoulder(rwy_polys, slivers, pvmt_accum);
         }
     }
 
@@ -410,11 +387,14 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
     tgPolygon apt_base, apt_clearing;
     if (boundary.size()) {
         TG_LOG(SG_GENERAL, SG_INFO, "Build " << boundary.size() << " Boundary Polys ");
+
         shapefile = "";
 
-        for (unsigned int i = 0; i < boundary.size(); i++) {
-            TG_LOG(SG_GENERAL, SG_DEBUG, "Build user-defined boundary " << i + 1 << " of " << boundary.size());
-            boundary[i]->BuildBtg(apt_base, apt_clearing, shapefile);
+        unsigned i = 0;
+        for (auto& b : boundary) {
+            TG_LOG(SG_GENERAL, SG_DEBUG, "Build user-defined boundary " << ++i << " of " << boundary.size());
+
+            b->BuildBtg(apt_base, apt_clearing, shapefile);
         }
     } else {
         apt_base = tgPolygon::Union(apt_base_polys);
@@ -523,13 +503,6 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
         poly = tgPolygon::RemoveCycles(poly);
         poly = tgPolygon::RemoveDups(poly);
         poly = tgPolygon::RemoveBadContours(poly);
-
-//        poly = tgPolygon::Simplify( poly );
-//        poly = tgPolygon::RemoveTinyContours( poly );
-//        poly = tgPolygon::RemoveSpikes( poly );
-//        poly = tgPolygon::RemoveDups( poly );
-//        poly = tgPolygon::RemoveBadContours( poly );
-//        poly = tgPolygon::RemoveTinyContours( poly );
 #endif
 
         line_polys[k] = poly;
@@ -539,33 +512,6 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
     TG_LOG(SG_GENERAL, SG_ALERT, "Finished cleaning polys for " << icao << " at " << DebugTimeToString(log_time));
 
     base_poly = tgPolygon::AddColinearNodes(base_poly, tmp_pvmt_nodes);
-    // base_poly = tgPolygon::Snap( base_poly, gSnap );
-
-    // Finally find slivers in base
-    //slivers.clear();
-    //tgPolygon::RemoveSlivers( base_poly, slivers );
-    //tgPolygon::MergeSlivers( rwy_polys, slivers );
-    //tgPolygon::MergeSlivers( pvmt_polys, slivers );
-
-#if 0
-    // Then snap rwy and pavement to grid (was done right after adding intermediate nodes...)
-    for ( unsigned int k = 0; k < rwy_polys.size(); ++k )
-    {
-    	tgPolygon poly = rwy_polys[k];
-        poly = tgPolygon::Snap(poly, gSnap);
-        poly = tgPolygon::RemoveDups( poly );
-        poly = tgPolygon::RemoveBadContours( poly );
-    	rwy_polys[k] = poly;
-    }
-    for ( unsigned int k = 0; k < pvmt_polys.size(); ++k )
-    {
-    	tgPolygon poly = pvmt_polys[k];
-        poly = tgPolygon::Snap(poly, gSnap);
-        poly = tgPolygon::RemoveDups( poly );
-        poly = tgPolygon::RemoveBadContours( poly );
-    	pvmt_polys[k] = poly;
-    }
-#endif
 
     cleanup_end.stamp();
     cleanup_time = cleanup_end - cleanup_start;
@@ -585,13 +531,6 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
             TG_LOG(SG_GENERAL, SG_DEBUG, "contours before " << rwy_polys[i].Contours() << " total points before = " << rwy_polys[i].TotalNodes());
             rwy_polys[i].Tesselate();
 
-#if 0
-            // dump the triangles for each poly
-            char desc[128];
-            sprintf( desc, "poly_%06d", i );
-            tgShapefile::FromTriangles( rwy_polys[i], debug_root, "rwy_polys", desc );
-#endif
-
             TG_LOG(SG_GENERAL, SG_DEBUG, "triangles after = " << rwy_polys[i].Triangles());
             rwy_polys[i].Texture();
         }
@@ -606,12 +545,6 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
             TG_LOG(SG_GENERAL, SG_DEBUG, "contours before " << pvmt_polys[i].Contours() << " total points before = " << pvmt_polys[i].TotalNodes());
             pvmt_polys[i].Tesselate();
 
-#if 0
-            char desc[128];
-            sprintf( desc, "poly_%06d", i );
-            tgShapefile::FromTriangles( pvmt_polys[i], debug_root, "pvmt_polys", desc );
-#endif
-
             TG_LOG(SG_GENERAL, SG_DEBUG, "triangles after = " << pvmt_polys[i].Triangles());
             pvmt_polys[i].Texture();
         }
@@ -626,12 +559,6 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
             TG_LOG(SG_GENERAL, SG_DEBUG, "contours before " << line_polys[i].Contours() << " total points before = " << line_polys[i].TotalNodes());
             line_polys[i].Tesselate();
 
-#if 0
-            char desc[128];
-            sprintf( desc, "poly_%06d", i );
-            tgShapefile::FromTriangles( line_polys[i], debug_root, "line_polys", desc );
-#endif
-
             TG_LOG(SG_GENERAL, SG_DEBUG, "triangles after = " << line_polys[i].Triangles());
             line_polys[i].Texture();
         }
@@ -640,12 +567,6 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
     TG_LOG(SG_GENERAL, SG_INFO, "Tesselating base poly : " << base_poly.Contours() << " contours ");
     base_poly.Tesselate();
 
-#if 0
-    char desc[128];
-    sprintf( desc, "poly" );
-    tgShapefile::FromTriangles( base_poly, debug_root, "base_poly", desc );
-#endif
-
     TG_LOG(SG_GENERAL, SG_INFO, "Tesselating base poly - done : Triangles = " << base_poly.Triangles());
     // should we texture base here?
     base_poly.SetTexMethod(TG_TEX_BY_GEODE, b.get_center_lat());
@@ -661,15 +582,6 @@ void Airport::BuildBtg(const std::string& root, const string_list& elev_src)
 
     triangulation_time = triangulation_end - triangulation_start;
 
-#if 0
-    // CheckZFighting( "post triangulation", debug_root, base_poly, rwy_polys, pvmt_polys );
-    if ( CheckZFightingTriangles( "post triangulation tris", debug_root, base_poly, rwy_polys, pvmt_polys ) ) {
-        char cmd[128];
-        snprintf(cmd, 128, "echo %s >> zfight.txt\n", icao.c_str());
-        system (cmd);
-    }
-#endif
-
     //
     // We should now have the runway polygons all generated with their
     // corresponding triangles and texture coordinates, and the
diff --git a/src/Airports/GenAirports850/airport.hxx b/src/Airports/GenAirports/airport.hxx
similarity index 100%
rename from src/Airports/GenAirports850/airport.hxx
rename to src/Airports/GenAirports/airport.hxx
diff --git a/src/Airports/GenAirports850/apt_math.cxx b/src/Airports/GenAirports/apt_math.cxx
similarity index 100%
rename from src/Airports/GenAirports850/apt_math.cxx
rename to src/Airports/GenAirports/apt_math.cxx
diff --git a/src/Airports/GenAirports850/apt_math.hxx b/src/Airports/GenAirports/apt_math.hxx
similarity index 100%
rename from src/Airports/GenAirports850/apt_math.hxx
rename to src/Airports/GenAirports/apt_math.hxx
diff --git a/src/Airports/GenAirports850/beznode.hxx b/src/Airports/GenAirports/beznode.hxx
similarity index 100%
rename from src/Airports/GenAirports850/beznode.hxx
rename to src/Airports/GenAirports/beznode.hxx
diff --git a/src/Airports/GenAirports850/closedpoly.cxx b/src/Airports/GenAirports/closedpoly.cxx
similarity index 100%
rename from src/Airports/GenAirports850/closedpoly.cxx
rename to src/Airports/GenAirports/closedpoly.cxx
diff --git a/src/Airports/GenAirports850/closedpoly.hxx b/src/Airports/GenAirports/closedpoly.hxx
similarity index 100%
rename from src/Airports/GenAirports850/closedpoly.hxx
rename to src/Airports/GenAirports/closedpoly.hxx
diff --git a/src/Airports/GenAirports850/debug.cxx b/src/Airports/GenAirports/debug.cxx
similarity index 100%
rename from src/Airports/GenAirports850/debug.cxx
rename to src/Airports/GenAirports/debug.cxx
diff --git a/src/Airports/GenAirports850/debug.hxx b/src/Airports/GenAirports/debug.hxx
similarity index 100%
rename from src/Airports/GenAirports850/debug.hxx
rename to src/Airports/GenAirports/debug.hxx
diff --git a/src/Airports/GenAirports850/elevations.cxx b/src/Airports/GenAirports/elevations.cxx
similarity index 100%
rename from src/Airports/GenAirports850/elevations.cxx
rename to src/Airports/GenAirports/elevations.cxx
diff --git a/src/Airports/GenAirports850/elevations.hxx b/src/Airports/GenAirports/elevations.hxx
similarity index 100%
rename from src/Airports/GenAirports850/elevations.hxx
rename to src/Airports/GenAirports/elevations.hxx
diff --git a/src/Airports/GenAirports850/genapts.sh b/src/Airports/GenAirports/genapts.sh
similarity index 96%
rename from src/Airports/GenAirports850/genapts.sh
rename to src/Airports/GenAirports/genapts.sh
index 31bd0672..6e9dacab 100755
--- a/src/Airports/GenAirports850/genapts.sh
+++ b/src/Airports/GenAirports/genapts.sh
@@ -33,7 +33,7 @@ APTDAT=${HOME}/live/airfield/v10+/apt.dat
 DEM="--dem-path=SRTM2-VFP-3-NE --dem-path=SRTM2-VFP-3-NW \
      --dem-path=SRTM2-VFP-3-SE --dem-path=SRTM2-VFP-3-SW"
 
-GENAPTS=${HOME}/terragear/bin/genapts850
+GENAPTS=${HOME}/terragear/bin/genapts
 
 #${GENAPTS} --threads --input=${APTDAT} --work=${WORKBASE} ${DEM} ${NUDGE} ${SPAT}
 ${GENAPTS} --input=${APTDAT} --work=${WORKBASE} ${DEM} ${NUDGE} ${SPAT}
diff --git a/src/Airports/GenAirports850/global.hxx b/src/Airports/GenAirports/global.hxx
similarity index 100%
rename from src/Airports/GenAirports850/global.hxx
rename to src/Airports/GenAirports/global.hxx
diff --git a/src/Airports/GenAirports850/helipad.cxx b/src/Airports/GenAirports/helipad.cxx
similarity index 100%
rename from src/Airports/GenAirports850/helipad.cxx
rename to src/Airports/GenAirports/helipad.cxx
diff --git a/src/Airports/GenAirports850/helipad.hxx b/src/Airports/GenAirports/helipad.hxx
similarity index 99%
rename from src/Airports/GenAirports850/helipad.hxx
rename to src/Airports/GenAirports/helipad.hxx
index 2965dc99..dc147118 100644
--- a/src/Airports/GenAirports850/helipad.hxx
+++ b/src/Airports/GenAirports/helipad.hxx
@@ -18,6 +18,7 @@
 
 #include <memory>
 
+#include "runway.hxx"
 #include <terragear/tg_polygon.hxx>
 #include <terragear/tg_accumulator.hxx>
 #include <terragear/tg_light.hxx>
diff --git a/src/Airports/GenAirports850/lights.cxx b/src/Airports/GenAirports/lights.cxx
similarity index 100%
rename from src/Airports/GenAirports850/lights.cxx
rename to src/Airports/GenAirports/lights.cxx
diff --git a/src/Airports/GenAirports850/linearfeature.cxx b/src/Airports/GenAirports/linearfeature.cxx
similarity index 100%
rename from src/Airports/GenAirports850/linearfeature.cxx
rename to src/Airports/GenAirports/linearfeature.cxx
diff --git a/src/Airports/GenAirports850/linearfeature.hxx b/src/Airports/GenAirports/linearfeature.hxx
similarity index 100%
rename from src/Airports/GenAirports850/linearfeature.hxx
rename to src/Airports/GenAirports/linearfeature.hxx
diff --git a/src/Airports/GenAirports850/linked_objects.cxx b/src/Airports/GenAirports/linked_objects.cxx
similarity index 100%
rename from src/Airports/GenAirports850/linked_objects.cxx
rename to src/Airports/GenAirports/linked_objects.cxx
diff --git a/src/Airports/GenAirports850/linked_objects.hxx b/src/Airports/GenAirports/linked_objects.hxx
similarity index 100%
rename from src/Airports/GenAirports850/linked_objects.hxx
rename to src/Airports/GenAirports/linked_objects.hxx
diff --git a/src/Airports/GenAirports850/main.cxx b/src/Airports/GenAirports/main.cxx
similarity index 98%
rename from src/Airports/GenAirports850/main.cxx
rename to src/Airports/GenAirports/main.cxx
index bee503cd..79869ed5 100644
--- a/src/Airports/GenAirports850/main.cxx
+++ b/src/Airports/GenAirports/main.cxx
@@ -147,7 +147,7 @@ int main(int argc, char** argv)
     // parse arguments
     std::string work_dir = "";
     std::string input_file = "";
-    std::string summary_file = "./genapt850.csv";
+    std::string summary_file = "./genapt.csv";
     std::string start_id = "";
     std::string airport_id = "";
     int num_threads = 1;
@@ -212,7 +212,7 @@ int main(int argc, char** argv)
     std::string airportareadir = work_dir + "/AirportArea";
 
     // this is the main program -
-    TG_LOG(SG_GENERAL, SG_INFO, "Genapts850 version " << getTGVersion() << " running with " << num_threads << " threads");
+    TG_LOG(SG_GENERAL, SG_INFO, "Genapts version " << getTGVersion() << " running with " << num_threads << " threads");
     TG_LOG(SG_GENERAL, SG_INFO, "Launch command was " << argv[0]);
     TG_LOG(SG_GENERAL, SG_INFO, "Input file = " << input_file);
     TG_LOG(SG_GENERAL, SG_INFO, "Work directory = " << work_dir);
diff --git a/src/Airports/GenAirports850/object.cxx b/src/Airports/GenAirports/object.cxx
similarity index 100%
rename from src/Airports/GenAirports850/object.cxx
rename to src/Airports/GenAirports/object.cxx
diff --git a/src/Airports/GenAirports850/object.hxx b/src/Airports/GenAirports/object.hxx
similarity index 100%
rename from src/Airports/GenAirports850/object.hxx
rename to src/Airports/GenAirports/object.hxx
diff --git a/src/Airports/GenAirports850/output.cxx b/src/Airports/GenAirports/output.cxx
similarity index 100%
rename from src/Airports/GenAirports850/output.cxx
rename to src/Airports/GenAirports/output.cxx
diff --git a/src/Airports/GenAirports850/output.hxx b/src/Airports/GenAirports/output.hxx
similarity index 100%
rename from src/Airports/GenAirports850/output.hxx
rename to src/Airports/GenAirports/output.hxx
diff --git a/src/Airports/GenAirports850/parser.cxx b/src/Airports/GenAirports/parser.cxx
similarity index 100%
rename from src/Airports/GenAirports850/parser.cxx
rename to src/Airports/GenAirports/parser.cxx
diff --git a/src/Airports/GenAirports850/parser.hxx b/src/Airports/GenAirports/parser.hxx
similarity index 100%
rename from src/Airports/GenAirports850/parser.hxx
rename to src/Airports/GenAirports/parser.hxx
diff --git a/src/Airports/GenAirports850/runway.cxx b/src/Airports/GenAirports/runway.cxx
similarity index 100%
rename from src/Airports/GenAirports850/runway.cxx
rename to src/Airports/GenAirports/runway.cxx
diff --git a/src/Airports/GenAirports850/runway.hxx b/src/Airports/GenAirports/runway.hxx
similarity index 100%
rename from src/Airports/GenAirports850/runway.hxx
rename to src/Airports/GenAirports/runway.hxx
diff --git a/src/Airports/GenAirports850/rwy_gen.cxx b/src/Airports/GenAirports/rwy_gen.cxx
similarity index 100%
rename from src/Airports/GenAirports850/rwy_gen.cxx
rename to src/Airports/GenAirports/rwy_gen.cxx
diff --git a/src/Airports/GenAirports850/rwy_simple.cxx b/src/Airports/GenAirports/rwy_simple.cxx
similarity index 100%
rename from src/Airports/GenAirports850/rwy_simple.cxx
rename to src/Airports/GenAirports/rwy_simple.cxx
diff --git a/src/Airports/GenAirports850/scheduler.cxx b/src/Airports/GenAirports/scheduler.cxx
similarity index 100%
rename from src/Airports/GenAirports850/scheduler.cxx
rename to src/Airports/GenAirports/scheduler.cxx
diff --git a/src/Airports/GenAirports850/scheduler.hxx b/src/Airports/GenAirports/scheduler.hxx
similarity index 100%
rename from src/Airports/GenAirports850/scheduler.hxx
rename to src/Airports/GenAirports/scheduler.hxx
diff --git a/src/Airports/GenAirports850/taxiway.cxx b/src/Airports/GenAirports/taxiway.cxx
similarity index 100%
rename from src/Airports/GenAirports850/taxiway.cxx
rename to src/Airports/GenAirports/taxiway.cxx
diff --git a/src/Airports/GenAirports850/taxiway.hxx b/src/Airports/GenAirports/taxiway.hxx
similarity index 100%
rename from src/Airports/GenAirports850/taxiway.hxx
rename to src/Airports/GenAirports/taxiway.hxx
diff --git a/src/Airports/GenAirports850/trafficFlow.cxx b/src/Airports/GenAirports/trafficFlow.cxx
similarity index 100%
rename from src/Airports/GenAirports850/trafficFlow.cxx
rename to src/Airports/GenAirports/trafficFlow.cxx
diff --git a/src/Airports/GenAirports850/trafficFlow.hxx b/src/Airports/GenAirports/trafficFlow.hxx
similarity index 100%
rename from src/Airports/GenAirports850/trafficFlow.hxx
rename to src/Airports/GenAirports/trafficFlow.hxx
diff --git a/src/Airports/GenAirports850/.gitignore b/src/Airports/GenAirports850/.gitignore
deleted file mode 100644
index 410f82f3..00000000
--- a/src/Airports/GenAirports850/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-genapts850