some fallbacks for older maps, disclaimer in readme for older maps

README.md

@@ -20,6 +20,7 @@ Although we would say that using `grad_meh` is intuitive and mostly self-explana
 - To reduce complexity we only allow one export process at a time.
 - To reduce complexity it is not possible to stop a running export reliably, except by killing the game.
 - MEH cannot export maps included in `.ebo` files, because those are encrypted and therefore we cannot get to the map files. 
+- MEH will have some difficulties with older maps (e.g. Fallujah, Clafghan), where it fails to export roads and tile the sat image correctly.
 
 ## Output
 We export the following from Arma 3 maps:

src/geojsons.cpp

@@ -808,6 +808,13 @@ void writeGeojsons(grad_aff::Wrp& wrp, std::filesystem::path& basePathGeojson, c
         }
 
         auto pboPath = findPboPath(modelPath);
+
+        if (pboPath.empty()) {
+            modelMapTypes[i] = {};
+            modelInfos[i] = {};
+            break;
+        }
+
         std::shared_ptr<grad_aff::Pbo> pbo = {};
         auto res = pboMap.find(pboPath);
         if (res == pboMap.end()) {
@@ -843,6 +850,10 @@ void writeGeojsons(grad_aff::Wrp& wrp, std::filesystem::path& basePathGeojson, c
                     for (int j = 0; j < odol.lods.size(); j++) {
                         if (odol.lods[j].lodType == LodType::SPECIAL_LOD) {
                             geoIndex = j;
+                            break;
+                        }
+                        if (geoIndex == -1 && odol.lods[j].lodType == LodType::GEOMETRY) { // Fallback
+                            geoIndex = j; 
                         }
                     }
                     auto memLod = odol.readLod(geoIndex);

src/main.cpp

@@ -148,6 +148,11 @@ void writePreviewImage(const std::string& worldName, std::filesystem::path& base
     }
 
     auto pboPath = findPboPath(picturePath);
+
+    if (pboPath.empty()) {
+        return;
+    }
+
     grad_aff::Pbo prewviewPbo(pboPath.string());
 
     auto paa = grad_aff::Paa();