diff --git a/package-lock.json b/package-lock.json
index eb0a788..f686d50 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6395,6 +6395,11 @@
         "randombytes": "^2.0.0"
       }
     },
+    "dijkstrajs": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/dijkstrajs/-/dijkstrajs-1.0.1.tgz",
+      "integrity": "sha1-082BIh4+pAdCz83lVtTpnpjdxxs="
+    },
     "dir-glob": {
       "version": "2.2.2",
       "resolved": "https://registry.npmjs.org/dir-glob/-/dir-glob-2.2.2.tgz",
diff --git a/package.json b/package.json
index d368510..e2d3fcf 100644
--- a/package.json
+++ b/package.json
@@ -58,6 +58,7 @@
   "dependencies": {
     "@turf/turf": "^5.1.6",
     "axios": "^0.18.0",
+    "dijkstrajs": "^1.0.1",
     "electron-debug": "^3.0.1",
     "element-ui": "^2.12.0",
     "file-url": "^3.0.0",
diff --git a/src/renderer/components/CheckPanel.vue b/src/renderer/components/CheckPanel.vue
new file mode 100644
index 0000000..1fd936d
--- /dev/null
+++ b/src/renderer/components/CheckPanel.vue
@@ -0,0 +1,46 @@
+<template>
+  <div>
+    <h1 class="leaflet-sidebar-header">
+      Check Result
+      <div class="leaflet-sidebar-close">
+        <i class="fa fa-caret-left"></i>
+      </div>
+    </h1>
+    <div id="panel" width="100%">            
+      <el-row v-for="(result,idx) in results" :key="idx">
+        <el-col :span="7">{{ result.id }}</el-col>
+        <el-col :span="15">{{ result.message }}</el-col>
+      </el-row>
+    </div>
+  </div>
+</template>
+
+<script lang="js">
+  export default {
+    name: 'settings-panel',
+    components: {},
+    props: [],
+    mounted () {
+    },
+    data () {
+      return {
+      }
+    },
+    methods: {
+    },
+    computed: {
+      results: function () {
+        return this.$store.state.Check.results
+      }
+    }
+  }
+</script>
+
+<style>
+.el-row {
+  margin-bottom: 1px;
+}
+.el-col {
+  border-radius: 1px;
+}
+</style>
diff --git a/src/renderer/components/EditBar.vue b/src/renderer/components/EditBar.vue
index 43d6aaa..49e23ad 100644
--- a/src/renderer/components/EditBar.vue
+++ b/src/renderer/components/EditBar.vue
@@ -1,7 +1,12 @@
 <template>
   <div id="EditBar">
     <EditButton icon="fas fa-edit" v-on:click="edit" :show="!editing" tooltip="Edit"></EditButton>
-    <EditButton icon="fas fa-undo" v-on:click="centerDialogVisible = true" :show="editing" tooltip="Undo"></EditButton>
+    <EditButton
+      icon="fas fa-undo"
+      v-on:click="centerDialogVisible = true"
+      :show="editing"
+      tooltip="Undo"
+    ></EditButton>
     <el-dialog title="Reload" :visible.sync="centerDialogVisible" width="30%" center>
       <span style="center">Reload from last save? You will lose the current edits.</span>
       <span slot="footer" class="dialog-footer">
@@ -14,9 +19,25 @@
     </el-dialog>
 
     <EditButton icon="fas fa-save" v-on:click="save" :show="editing" tooltip="Save"></EditButton>
-    <EditButton icon="fas fa-draw-polygon" v-on:click="drawPolyline" :show="editing" tooltip="Draw Taxiline"></EditButton>
-    <EditButton icon="fas fa-parking" v-on:click="drawParking" :show="editing" tooltip="Draw Parking"></EditButton>
+    <EditButton
+      icon="fas fa-draw-polygon"
+      v-on:click="drawPolyline"
+      :show="editing"
+      tooltip="Draw Taxiline"
+    ></EditButton>
+    <EditButton
+      icon="fas fa-parking"
+      v-on:click="drawParking"
+      :show="editing"
+      tooltip="Draw Parking"
+    ></EditButton>
     <EditButton icon="fas fa-trash-alt" v-on:click="deleteFeature" :show="editing" tooltip="Remove"></EditButton>
+    <EditButton icon="far fa-check-square" v-on:click="showCheck" :show="editing" tooltip="Check"></EditButton>
+    <el-dialog title="Checking" width="30%" center :visible.sync="checkDialogVisible">
+      <el-container direction="vertical">
+        <el-progress :percentage="Number(((progress / max)*100).toPrecision(3))" v-if="max>0"></el-progress>
+      </el-container>
+    </el-dialog>
   </div>
 </template>
 
@@ -24,10 +45,14 @@
 /* eslint-disable */
   import EditButton from './EditButton'
   import Vue from 'vue'
+
+  import fileUrl from 'file-url'
+  const path = require('path')
+
   export default {
     components: { EditButton },
     data () {
-      return {isEditing: false, centerDialogVisible: false, saveDialogVisible: false}
+      return {isEditing: false, centerDialogVisible: false, saveDialogVisible: false, checkDialogVisible: false, checking: false, progress: 0, max: 0}
     },
     created () {
     },
@@ -58,6 +83,75 @@
             Vue.set(this, 'saveDialogVisible', false)
           }, this)
       },
+      pollData () {
+        var workery = this.worker
+        var view = this
+        workery.polling = setInterval(() => {
+          if (workery != null) {
+            view.max = Number(workery.max)
+            view.progress = Number(workery.progress)
+            view.scanning = Boolean(workery.checking)
+            workery.view = view
+          }
+        }, 1000)
+      },
+
+      check () {
+        try {
+          this.scanning = true
+          const winURL = process.env.NODE_ENV === 'development'
+            ? `http://localhost:9080/src/renderer/utils/check.js`
+            : `file://${__dirname}/check.js`
+          console.log('make a worker: ', path.resolve(__dirname, 'check.js'))
+
+          const worker = new Worker(winURL)
+          console.log(fileUrl('src/renderer/utils/check.js'))
+
+          worker.checking = this.checking
+          worker.max = this.max
+          worker.view = this
+          worker.editLayer = this.$parent.$parent.$refs.editLayer
+          worker.progress = 0
+          // var worker = new Worker(fileUrl('src/renderer/utils/worker.js'))
+          this.worker = worker
+          var xml = []
+          this.$parent.$parent.$refs.editLayer.groundnetLayerGroup.eachLayer(l => {
+            console.log(l)
+            xml.push(l)
+          })
+
+          var features = xml.map(this.featuresMapper).filter(n => n)
+
+          worker.postMessage(['check', features ] )
+          this.pollData()
+          // the reply
+          var store = this.$store
+          worker.onmessage = function (e) {
+            if (e.data === 'checkStarted') {
+              this.progress = 0
+              this.max = 4
+            } else if (e.data[0] === 'DONE') {
+              console.log('DONE')
+              store.dispatch('setResults', e.data[1])
+              worker.terminate()
+              worker.view.max = 0
+              worker.view.checkDialogVisible = false
+              clearInterval(this.polling)
+              this.checking = false
+            } else if (e.data.length > 0) {
+              if (e.data[0] === 'max') {
+                this.max = e.data[1]
+              }
+              if (e.data[0] === 'progress') {
+                this.progress += e.data[1]
+              }
+            }
+            // console.log(e.data)
+          }
+        } catch (err) {
+          console.error(err)
+        }
+      },
       drawPolyline () {
         this.$parent.$parent.$refs.editLayer.drawPolyline()
       },
@@ -66,6 +160,24 @@
       },
       deleteFeature () {
         this.$parent.$parent.$refs.editLayer.deleteFeature()
+      },
+      showCheck() {
+        Vue.set(this, 'checkDialogVisible', true)
+        this.check()
+      },
+      featuresMapper(o) {
+        if (o instanceof L.ParkingSpot) {
+          return { 'index': Number(o['id']), '_leaflet_id': o._leaflet_id, 'type': 'parking', 'name': o.options.attributes.name, 'radius': String(o.options.attributes.radius) };
+        } else if (o instanceof L.RunwayNode) {
+          console.log(o)
+          return { 'index': Number(o['glueindex']), '_leaflet_id': o._leaflet_id, 'type': 'runway' };
+        } else if (o instanceof L.Polyline) {
+          console.log(o)
+          return { 'start': Number(o['begin']), 'end': Number(o['end']), '_leaflet_id': o._leaflet_id, 'type': 'poly' };
+        } else {
+          console.log('Unknown Type ')
+          console.log(typeof o)
+        }
       }
     },
     computed: {
diff --git a/src/renderer/components/EditLayer.vue b/src/renderer/components/EditLayer.vue
index 366e1cc..8dab128 100644
--- a/src/renderer/components/EditLayer.vue
+++ b/src/renderer/components/EditLayer.vue
@@ -1,7 +1,4 @@
 <template>
-  <section class="edit-layer">
-    <h1>edit-layer Component</h1>
-  </section>
 </template>
 
 <script lang="js">
@@ -13,11 +10,13 @@
   import {extendTaxiSegment} from '../loaders/TaxiwaySegmentExtender'
   import {writeGroundnetXML} from '../loaders/groundnet_writer'
   import L2 from 'leaflet-textpath'
+  import Vue from 'vue'
 
   // import {LSymbol} from 'leaflet-polylinedecorator'
 
   export default {
     name: 'edit-layer',
+    components: {},
     props: [],
     created () {
       console.log(LMap)
@@ -66,15 +65,14 @@
     },
     data () {
       return {
-        maxId: 1, icao: String
+        maxId: 1, icao: String, checking: false
       }
     },
     methods: {
       load (icao, force) {        
         if (this.groundnetLayerGroup !== undefined) {
           this.groundnetLayerGroup.removeFrom(this.$parent.mapObject)
-        }
-        
+        }        
 
         this.icao = icao
         this.groundnetLayerGroup = readGroundnetXML(this.$store.state.Settings.settings.airportsDirectory, icao, force)
@@ -129,6 +127,9 @@
           this.deferredMountedTo(this.$parent.mapObject)
         }
       },
+      showCheck() {
+        Vue.set(this, 'checking', true)
+      },
       enableEdit () {
         this.editable = true
         this.featureLookup = [];
@@ -264,14 +265,14 @@
           if (element instanceof L.RunwayNode) {
             if (isOnRunway === 0) {
               // We shouldn't have a RunwayNode
-              element.removeFrom(layerGroup);
+              element.removeFrom(this.groundnetLayerGroup);
               this.featureLookup[nIndex].splice(index,1);              
             }
             hasRunwayNode = true;
           } else if (element instanceof L.HoldNode) {
             if (!isHoldPoint) {
               // We shouldn't have a RunwayNode
-              element.removeFrom(layerGroup);
+              element.removeFrom(this.groundnetLayerGroup);
               this.featureLookup[nIndex].splice(index,1);              
             } else {
               var fa_icon;
@@ -322,9 +323,11 @@
           });
           const node = new L.RunwayNode(latlng, { icon: icon });
           node.glueindex = nIndex;
-          node.addTo(layerGroup);
+          node.addTo(this.groundnetLayerGroup);
           this.featureLookup[nIndex].push(node);
+          node.featureLookup = this.featureLookup;
           node.addListeners();
+          node.extensions();
         }
         if (!hasHoldPointNode && isHoldPoint) {
           var fa_icon = null;
@@ -341,9 +344,11 @@
           });
           const node = new L.HoldNode(latlng, { icon: icon });
           node.glueindex = nIndex;
-          node.addTo(layerGroup);
+          node.addTo(this.groundnetLayerGroup);
+          node.featureLookup = this.featureLookup;
           this.featureLookup[nIndex].push(node);
           node.addListeners();
+          node.extensions();
         }
       },
       closestLayerSnap (eventLatlng, snap) {
@@ -398,6 +403,7 @@
         const circle = new L.ParkingSpot(event.latlng, {attributes: {radius: 20, heading: 0}})
         circle.id = (++this.groundnetLayerGroup.maxId)
         circle.addTo(this.groundnetLayerGroup)
+        circle.featureLookup = this.featureLookup
         circle.enableEdit()
         circle.extensions()
         circle.addListeners()
diff --git a/src/renderer/components/LeafletSidebar.vue b/src/renderer/components/LeafletSidebar.vue
index e65e4e5..74b55dc 100644
--- a/src/renderer/components/LeafletSidebar.vue
+++ b/src/renderer/components/LeafletSidebar.vue
@@ -7,6 +7,7 @@
             <li><a href="#edit" role="tab"><i class="fas fa-edit"></i></a></li>
             <li><a href="#search" role="tab"><i class="fa fa-search"></i></a></li>
             <li><a href="#scan" role="tab"><i class="fa fa-sync"></i></a></li>
+            <li><a href="#check" role="tab"><i class="far fa-check-square"></i></a></li>
         </ul>
 
         <ul role="tablist"> <!-- bottom aligned tabs -->
@@ -42,6 +43,9 @@
         <div class="leaflet-sidebar-pane" id="settings">
           <SettingsPanel></SettingsPanel>
         </div>
+        <div class="leaflet-sidebar-pane" id="check">
+          <CheckPanel></CheckPanel>
+        </div>
     </div>
 </div>  
 </template>
@@ -52,17 +56,18 @@
   import {} from 'leaflet-sidebar-v2'
   import L from 'leaflet'
   import AirportEdit from './AirportEdit'
+  import CheckPanel from './CheckPanel'
   import ParkingEdit from './ParkingEdit'
   import ArcEdit from './ArcEdit'
-  import NodeEdit from './NodeEdit'
-  import SettingsPanel from './SettingsPanel'
-  import RunScan from './RunScan'
-  import Search from './Search'
   import FileSelect from './FileSelect'
+  import NodeEdit from './NodeEdit'
+  import RunScan from './RunScan'
+  import SettingsPanel from './SettingsPanel'
+  import Search from './Search'
 
   export default {
     name: 'leaflet-sidebar',
-    components: { AirportEdit, ArcEdit, NodeEdit, ParkingEdit, SettingsPanel, RunScan, FileSelect, Search },
+    components: { AirportEdit, ArcEdit, CheckPanel, NodeEdit, ParkingEdit, SettingsPanel, RunScan, FileSelect, Search },
     props: [],
     mounted () {
       this.add()
diff --git a/src/renderer/loaders/RunwayNode.js b/src/renderer/loaders/RunwayNode.js
index f2659cd..504cea2 100644
--- a/src/renderer/loaders/RunwayNode.js
+++ b/src/renderer/loaders/RunwayNode.js
@@ -43,6 +43,7 @@ L.RunwayNode = L.Marker.extend({
         });
     },
     extensions: function (editLayer) {
+        this.options.attributes = {};
         if (typeof this.featureLookup[this.glueindex] === 'undefined') {
             this.featureLookup[this.glueindex] = new Array();
         }
diff --git a/src/renderer/store/modules/Check.js b/src/renderer/store/modules/Check.js
new file mode 100644
index 0000000..71f99c5
--- /dev/null
+++ b/src/renderer/store/modules/Check.js
@@ -0,0 +1,24 @@
+const state = {
+  results: []
+}
+
+const mutations = {
+  'CHECK_RESULTS' (state, results) {
+    state.results = results
+  }
+}
+
+const plugins = []
+
+const actions = {
+  async setResults (context, results) {
+    context.commit('CHECK_RESULTS', results)
+  }
+}
+
+export default {
+  state,
+  mutations,
+  actions,
+  plugins
+}
diff --git a/src/renderer/utils/airports copy.js b/src/renderer/utils/airports copy.js
deleted file mode 100644
index a38d729..0000000
--- a/src/renderer/utils/airports copy.js	
+++ /dev/null
@@ -1,95 +0,0 @@
-/* eslint-disable */
-const loki = require('lokijs');
-const fs = require('fs');
-
-var db = new loki('airports_DB.json');
-var features = null;
-
-export async function init() {
-    var promise = new Promise(function (resolve, reject) {
-        console.log("Init " + (features == null));
-        if (features == null) {
-            console.log("Loading DB");
-            db.loadDatabase({}, function (err) {
-                if (err) {
-                    console.error("Error loading DB");
-                    console.error(err);
-                    db.addCollection('features', {
-                        unique: ["properties.icao"], autoupdate: true
-                    });
-                    features = db.getCollection('features');
-                }
-                features = db.getCollection('features');
-                if( features == null ){
-                    db.addCollection('features', {
-                        unique: ["properties.icao"], autoupdate: true
-                    });
-                    features = db.getCollection('features');
-                }
-                console.log("Loaded " + features.count() + " features");
-                resolve(features);
-            });
-        }
-        else {
-            resolve(features);
-        }
-    });
-    return promise;
-}
-
-export function getAirport(apts, icao) {
-    console.log("Getting Airport " + icao);
-    var results = apts.where(function (f) {
-        return f.properties['icao'] === icao;
-    });
-    var feature;
-    if (results.length == 0) {
-        feature = {
-            "type": "Feature",
-            'properties': { 'icao': icao, 'twr': false, 'threshold': false, 'flights': 0 },
-            'geometry': {
-                "type": "Point"
-            }
-        };
-        feature = apts.insert(feature);   
-        // apts.update(feature);
-        console.log("Added New");
-        console.log(JSON.stringify(feature));
-        return feature;
-    }
-    else {
-        console.debug("retrieved " + JSON.stringify(results[0]));
-        return results[0];
-    }
-
-}
-
-export function save() {
-    if (!features || !features.data)
-        return;
-    var mappedData = features.data.map(function (f) {
-        delete f.meta;
-        delete f.$loki;
-        if(f.properties.airlines) {
-            f.properties.airlines = f.properties.airlines.join(' ');
-        }
-        else {
-            f.properties.airlines = [];
-        }
-
-        return f;
-    });
-
-    mappedData = mappedData.filter(feature => feature.properties['twr'] || feature.properties['threshold']);
-
-    //console.log(mappedData);
-    var featureCollection = { type: "FeatureCollection", features: mappedData };
-
-    let data = JSON.stringify(featureCollection, null, 2);
-    fs.writeFileSync('airports.json', data);
-    db.saveDatabase(function (err) {
-        if (err) {
-            console.error(err);
-        }
-    });
-}
diff --git a/src/renderer/utils/check.js b/src/renderer/utils/check.js
new file mode 100644
index 0000000..b082f30
--- /dev/null
+++ b/src/renderer/utils/check.js
@@ -0,0 +1,141 @@
+/* eslint-disable */
+const winURL = process.env.NODE_ENV === 'development'
+    ? `http://localhost:9080/src/renderer/utils/`
+    : `file://D:/GIT/flightgear-airports/src/renderer/utils/`
+
+var path = require('path');
+const fs = require('fs');
+
+importScripts('../../../node_modules/dijkstrajs/dijkstra.js');
+
+const homedir = require('os').homedir();
+
+importScripts('logger.js');
+
+function errorReceiver(event) {
+    throw event.data;
+}
+
+onmessage = function (event) {
+    postMessage('checkStarted');
+    logger('info', 'Check Started');      
+    console.log(event.data);
+    if (event.data[0] === 'check') {
+        checkGroundnet(event.data[1]).then(result => {
+            console.log("DONE Checking");
+            postMessage(['DONE', result]);
+            // event.origin.webContents.send('scanFinished');
+        }
+        ).catch(result => {
+            console.log('Crashed');
+            console.log(result);
+            postMessage('DONE');
+        });
+    }
+};
+
+async function checkGroundnet(data) {
+    var promise = new Promise(function (resolve, reject) {
+        this.max = 4;
+        debugger;
+        var parkings = data.map(mapParkings).filter(n => n !== undefined);
+        var runwayNodes = data.map(mapRunwayNodes).filter(n => n !== undefined);
+        var edges = data.map(mapEdges).filter(n => n !== undefined);
+
+        var graph = {};
+        parkings.forEach(element => {
+            graph[element] = {};
+        });
+        runwayNodes.forEach(element => {
+            graph[element] = {};
+        });
+        edges.forEach(element => {
+            graph[element.start] = {};
+            graph[element.end] = {};
+        });
+        edges.forEach(element => {
+            var node1 = graph[element.start];
+            node1[element.end] = 1;
+            var node2 = graph[element.end];
+            node2[element.start] = 1;
+        });
+        var okNodes = [];
+        logger('info', graph);
+        parkings.forEach(parkingNode => {
+            runwayNodes.forEach(runwayNode => {
+               var ok = checkRoute(graph, parkingNode, runwayNode); 
+               if(ok) {
+                 okNodes.push(parkingNode);
+                 okNodes.push(runwayNode);
+               }
+               this.progress += 1;
+            });
+        });
+        okNodes = okNodes.filter((v,i) => okNodes.indexOf(v) === i);
+        var allNodes = parkings.concat(runwayNodes);
+        var notOkNodes = allNodes.filter((v,i) => okNodes.indexOf(v) < 0).map(id => {return {id:id, message:'Node not connected'}});
+        if (parkings.length === 0) {
+            notOkNodes.push({id:0, message:'No parkings'});
+        }
+        if (runwayNodes.length === 0) {
+            notOkNodes.push({id:0, message:'No Runwaynodes'});
+        }
+
+//        check1(graph);
+//        check2();
+//        this.progress += 1;
+        resolve(notOkNodes);
+    });
+    return promise;
+}
+
+function checkRoute(graph, from, to) {
+    try {
+        var pathD = this.dijkstra.find_path(graph, from, to);
+        if (pathD.length>0) {
+            console.log(pathD);        
+        }
+        return true;            
+    } catch (error) {
+        console.log('No route from ' + from + ' to ' + to);
+        return false;
+    }
+}
+
+function check1(graph) {
+    var graph1 = {
+        a: {b: 1, d: 1},
+        b: {a: 1, c: 1, e: 1},
+        c: {b: 1, f: 1},
+        d: {a: 1, e: 1, g: 1},
+        e: {b: 1, d: 1, f: 1, h: 1},
+        f: {c: 1, e: 1, i: 1},
+        g: {d: 1, h: 1},
+        h: {e: 1, g: 1, i: 1},
+        i: {f: 1, h: 1}
+    };
+    var path = this.dijkstra.find_path(graph, 'a', 'i');
+    console.log(path);
+}
+
+function check2(params) {
+    
+}
+
+var mapParkings = function (o) {
+    if(o.type === 'parking')
+      return o.index;
+    console.log(o);
+}
+
+var mapRunwayNodes = function (o) {
+    if(o.type === 'runway')
+      return o.index;
+    console.log(o);
+}
+
+var mapEdges = function (o) {
+    if(o.type === 'poly')
+      return {start: o.start, end: o.end};
+    console.log(o);
+}