Initial build

js/waypoint.js

@@ -144,7 +144,12 @@ let Waypoint = function (number, action, lat, lon, alt=0, p1=0, p2=0, p3=0, endM
             elevation = myJson.resourceSets[0].resources[0].elevations[0];
         }
         else {
-            elevation = "NA";
+            const response = await fetch('https://api.opentopodata.org/v1/aster30m?locations='+self.getLatMap()+','+self.getLonMap());
+            const myJson = await response.json();
+            elevation = myJson.results[0].elevation;
+            if (elevation == null) {
+                elevation = "N/A";
+            }
         }
         return elevation;
     }

js/waypointCollection.js

@@ -414,15 +414,27 @@ let WaypointCollection = function () {
         let lengthMission = self.getDistance(true);
         let totalMissionDistance = lengthMission[lengthMission.length -1].toFixed(1);
         let samples;
+        let sampleMaxNum;
+        let sampleDistance;
+
+        if (globalSettings.mapProviderType == 'bing') {
+            sampleMaxNum = 1024;
+            sampleDistance = 30;
+        } else {    // use opentopodata.org instead
+            sampleMaxNum = 99;
+            sampleDistance = 60;
+        }
+
         if (point2measure.length <= 2){
             samples = 1;
         }
-        else if (Math.trunc(totalMissionDistance/30) <= 1024 &&  point2measure.length > 2){
-            samples = Math.trunc(totalMissionDistance/30);
+        else if (Math.trunc(totalMissionDistance / sampleDistance) <= sampleMaxNum && point2measure.length > 2){
+            samples = Math.trunc(totalMissionDistance / sampleDistance);
         }
         else {
-            samples = 1024;
+            samples = sampleMaxNum;
         }
+
         if (globalSettings.mapProviderType == 'bing') {
             if (point2measure.length >1) {
                 const response = await fetch('http://dev.virtualearth.net/REST/v1/Elevation/Polyline?points='+point2measure+'&heights=ellipsoid&samples='+String(samples+1)+'&key='+globalSettings.mapApiKey);
@@ -436,7 +448,20 @@ let WaypointCollection = function () {
             }
         }
         else {
-            elevation = "NA";
+            let coordList = "";
+            point2measure.forEach(function (item) {
+                coordList += item + '|';
+            });
+            const response = await fetch('https://api.opentopodata.org/v1/aster30m?locations='+coordList+'&samples='+String(samples+1));
+            const myJson = await response.json();
+            var elevation = [];
+            for (var i = 0; i < myJson.results.length; i++){
+                if (myJson.results[i].elevation == null) {
+                    elevation[i] = 0;
+                } else {
+                    elevation[i] = myJson.results[i].elevation;
+                }
+            }
         }
         //console.log("elevation ", elevation);
         return [lengthMission, totalMissionDistance, samples, elevation, altPoint2measure, namePoint2measure, refPoint2measure];