diff --git a/js/geozone.js b/js/geozone.js
index f2b8a80dd..ee6e90d04 100644
--- a/js/geozone.js
+++ b/js/geozone.js
@@ -55,7 +55,7 @@ let GeozoneVertex = function (number, lat, lon) {
     return self;
 }
 
-let Geozone = function (type, shape, minAltitude, maxAltitude, radius, fenceAction, vertices, number = 0) {
+let Geozone = function (type, shape, minAltitude, maxAltitude, sealevelRef, radius, fenceAction, vertices, number = 0) {
     var self = {};
 
     self.setNumber = (data) => {
@@ -98,6 +98,14 @@ let Geozone = function (type, shape, minAltitude, maxAltitude, radius, fenceActi
         return maxAltitude;
     }
 
+    self.setSealevelRef = (data) => {
+        sealevelRef = data;
+    }
+
+    self.getSealevelRef = () => {
+        return sealevelRef;
+    }
+
     self.setRadius = (data) => {
         radius = data;
     }
@@ -168,6 +176,27 @@ let Geozone = function (type, shape, minAltitude, maxAltitude, radius, fenceActi
         vertices = [];
     }
 
+    self.getElevationFromServer = async function (lon, lat, globalSettings) {
+        let elevation = "N/A";
+        if (globalSettings.mapProviderType == 'bing') {
+            let elevationEarthModel = $('#elevationEarthModel').prop("checked") ? "ellipsoid" : "sealevel";
+
+            const response = await fetch('http://dev.virtualearth.net/REST/v1/Elevation/List?points='+lat+','+lon+'&heights='+elevationEarthModel+'&key='+globalSettings.mapApiKey);
+            const myJson = await response.json();
+            elevation = myJson.resourceSets[0].resources[0].elevations[0];
+        }
+        else {
+            const response = await fetch('https://api.opentopodata.org/v1/aster30m?locations='+lat+','+lon);
+            const myJson = await response.json();
+            if (myJson.status == "OK" && myJson.results[0].elevation != null) {
+                elevation = myJson.results[0].elevation;
+            }
+        }
+        return elevation;
+    }
+
+    return self;
+
     return self;
 }
 
diff --git a/js/geozoneCollection.js b/js/geozoneCollection.js
index e1ef668c0..66b5e666a 100644
--- a/js/geozoneCollection.js
+++ b/js/geozoneCollection.js
@@ -132,6 +132,7 @@ let GeozoneCollection = function() {
             buffer.push(BitHelper.specificByte(zone.getMaxAltitude(), 1));
             buffer.push(BitHelper.specificByte(zone.getMaxAltitude(), 2));
             buffer.push(BitHelper.specificByte(zone.getMaxAltitude(), 3));
+            buffer.push(zone.getSealevelRef());
             buffer.push(zone.getFenceAction());
             if (zone.getShape() == GeozoneShapes.CIRCULAR) { 
                 buffer.push(2);
diff --git a/js/msp/MSPHelper.js b/js/msp/MSPHelper.js
index 9a871958b..fa9d02ffd 100644
--- a/js/msp/MSPHelper.js
+++ b/js/msp/MSPHelper.js
@@ -1608,16 +1608,17 @@ var mspHelper = (function () {
             
             case MSPCodes.MSP2_INAV_GEOZONE:
                 var geozone = new Geozone(
-                    data.getUint8(0),
                     data.getUint8(1),
-                    data.getInt32(2, true),
-                    data.getInt32(6, true),
+                    data.getUint8(2),
+                    data.getInt32(3, true),
+                    data.getInt32(4, true),
+                    data.getUint8(11),
                     0,
-                    data.getInt8(10, true),
+                    data.getInt8(12, true),
                     null,
-                    data.getUint8(12, true),
+                    data.getUint8(14, true),
                 );
-                let verticesCount = data.getUint8(11, true);
+                let verticesCount = data.getUint8(13, true);
                 if (verticesCount == 0) {
                     break;
                 }
diff --git a/tabs/mission_control.html b/tabs/mission_control.html
index d031c5a33..41341702b 100644
--- a/tabs/mission_control.html
+++ b/tabs/mission_control.html
@@ -335,12 +335,18 @@
                                     <div class="point">
                                         <label class="point-label" for="zoneMinAlt" data-i18n="geozoneMinAlt"></label>
                                         <input type="number" id="geozoneMinAlt"></input>
+                                        <span id="geozoneMinAltM"></span>
                                     </div>
                                     <div class="point">
                                         <label class="point-label" for="zoneMaxAlt" data-i18n="geozoneMaxAlt"></label>
                                         <input type="number" id="geozoneMaxAlt"></input>
+                                        <span id="geozoneMaxAltM"></span><br/>
                                         <span data-i18n="geozoneInfiniteAlt"></span>
                                     </div>
+                                    <div class="point">
+                                        <label class="point-label" for="geozoneSeaLevelRef" data-i18n="missionSeaLevelRef"></label>
+                                        <input id="geozoneSeaLevelRef" type="checkbox" value="0" class="togglemedium" required>
+                                    </div>
                                     <div class="point">
                                         <label class="point-label" for="zoneAction" data-i18n="geozoneAction">Action:</label>
                                         <select name="zoneAction" id="geozoneAction">
diff --git a/tabs/mission_control.js b/tabs/mission_control.js
index a8ce25fb8..1ec24ecdc 100644
--- a/tabs/mission_control.js
+++ b/tabs/mission_control.js
@@ -31,6 +31,7 @@ const Plotly = require('./../js/libraries/plotly-latest.min');
 const interval = require('./../js/intervals');
 const { Geozone, GeozoneVertex, GeozoneType, GeozoneShapes, GeozoneFenceAction }  = require('./../js/geozone');
 const GeozoneCollection = require('./../js/geozoneCollection');
+const { event } = require('jquery');
 
 var MAX_NEG_FW_LAND_ALT = -2000; // cm
 
@@ -978,7 +979,7 @@ TABS.mission_control.initialize = function (callback) {
         let mapCenter = map.getView().getCenter();
         let midLon = Math.round(ol.proj.toLonLat(mapCenter)[0] * 1e7);
         let midLat = Math.round(ol.proj.toLonLat(mapCenter)[1] * 1e7);        
-        FC.GEOZONES.put(new Geozone(GeozoneType.INCLUSIVE, GeozoneShapes.CIRCULAR, 0, 10000, 20000, GeozoneFenceAction.NONE, [ new GeozoneVertex(0, midLat, midLon) ]));
+        FC.GEOZONES.put(new Geozone(GeozoneType.INCLUSIVE, GeozoneShapes.CIRCULAR, 0, 10000, false, 20000, GeozoneFenceAction.NONE, [ new GeozoneVertex(0, midLat, midLon) ]));
 
         selectedGeozone = FC.GEOZONES.last();
         renderGeozoneOptions();
@@ -1689,6 +1690,9 @@ TABS.mission_control.initialize = function (callback) {
             $('#geozoneType').val(selectedGeozone.getType());
             $('#geozoneMinAlt').val(selectedGeozone.getMinAltitude());
             $('#geozoneMaxAlt').val(selectedGeozone.getMaxAltitude());
+            $('#geozoneMinAltM').text(selectedGeozone.getMinAltitude() / 100 + " m");
+            $('#geozoneMaxAltM').text(selectedGeozone.getMaxAltitude()  / 100 + " m");
+            changeSwitchery($('#geozoneSeaLevelRef'), selectedGeozone.getSealevelRef());
             $('#geozoneAction').val(selectedGeozone.getFenceAction());
             $('#geozoneRadius').val(selectedGeozone.getRadius);
             if (selectedGeozone.getShape() == GeozoneShapes.CIRCULAR) {
@@ -3414,20 +3418,39 @@ TABS.mission_control.initialize = function (callback) {
         $('#geozoneMinAlt').on('change', event => {
             if (selectedGeozone) {
                 selectedGeozone.setMinAltitude($(event.currentTarget).val());
-                renderGeozonesOnMap();
+                renderGeozoneOptions();
             }
         });
         $('#geozoneMaxAlt').on('change', event => {
             if (selectedGeozone) {
                 selectedGeozone.setMaxAltitude($(event.currentTarget).val());
-                renderGeozonesOnMap();
+                renderGeozoneOptions();
+            }
+        });
+
+        $('#geozoneSeaLevelRef').on('change', event => {
+            if (selectedGeozone) {
+                const isChecked = $(event.currentTarget).prop('checked') ? 1 : 0;
+                selectedGeozone.setSealevelRef(isChecked);
+                (async () => {
+                    const vertex = selectedGeozone.getVertex(0);
+                    const elevation = await selectedGeozone.getElevationFromServer(vertex.getLonMap(), vertex.getLatMap(), globalSettings);
+
+                    if (isChecked) {
+                        selectedGeozone.setMinAltitude(Number(selectedGeozone.getMinAltitude()) + elevation * 100);
+                        selectedGeozone.setMaxAltitude(Number(selectedGeozone.getMaxAltitude()) + elevation * 100);
+                    } else {
+                        selectedGeozone.setMinAltitude(Number(selectedGeozone.getMinAltitude()) - elevation * 100);
+                        selectedGeozone.setMaxAltitude(Number(selectedGeozone.getMaxAltitude()) - elevation * 100);
+                    }
+                    renderGeozoneOptions();
+                })();
             }
         });
 
         $('#geozoneAction').on('change', event => {
             if (selectedGeozone) {
                 selectedGeozone.setFenceAction($(event.currentTarget).val());
-                renderGeozonesOnMap();
             }
         });
 
diff --git a/tabs/osd.js b/tabs/osd.js
index d0f41d8de..24bc91b53 100644
--- a/tabs/osd.js
+++ b/tabs/osd.js
@@ -1760,7 +1760,7 @@ OSD.constants = {
                     }
                 },{
                     name: 'COURSE_NEXT_GEOZONE',
-                    id: 159,
+                    id: 163,
                     min_version: '8.0.0',
                     enabled: function() {
                         return FC.isFeatureEnabled('GEOZONE');
@@ -1768,7 +1768,7 @@ OSD.constants = {
                     preview: FONT.symbol(SYM.DIR_TO_HOME)
                 }, {
                     name: 'HOR_DIST_TO_NEXT_GEOZONE',
-                    id: 160,
+                    id: 164,
                     min_version: '8.0.0',
                     enabled: function() {
                         return FC.isFeatureEnabled('GEOZONE');
@@ -1787,7 +1787,7 @@ OSD.constants = {
                 },
                 {
                     name: 'VERT_DIST_TO_NEXT_GEOZONE',
-                    id: 161,
+                    id: 165,
                     min_version: '8.0.0',
                     enabled: function() {
                         return FC.isFeatureEnabled('GEOZONE');