added esri imagery tiles layer

Author: Peter

web/src/main/webapp/js/main.js

@@ -363,10 +363,18 @@ function initMap(selectLayer) {
         subdomains: ['a', 'b', 'c']
     });
 
+    var mapLink = '<a href="http://www.esri.com/">Esri</a>';
+    var wholink = 'i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, and the GIS User Community';
+    var esriAerial = L.tileLayer('https://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/{z}/{y}/{x}', {
+                attribution: osmAttr + '&copy; ' + mapLink + ', ' + wholink,
+                maxZoom: 18
+            });
+
     var baseMaps = {
         "Lyrk": lyrk,
         "MapQuest": mapquest,
         "MapQuest Aerial": mapquestAerial,
+        "Esri Aerial": esriAerial,
         "OpenMapSurfer": openMapSurfer,
         "TF Transport": thunderTransport,
         "TF Cycle": thunderCycle,