Change maps source to use Wikimedia maps.

Add link to Wikimedia maps ToS.
If there's no data, show the map anyway.

src/core/operations/ShowOnMap.mjs

@@ -21,7 +21,7 @@ class ShowOnMap extends Operation {
 
         this.name = "Show on map";
         this.module = "Hashing";
-        this.description = "Displays co-ordinates on an OpenStreetMap slippy map.<br><br>Co-ordinates will be converted to decimal degrees before being shown on the map.<br><br>Supported formats:<ul><li>Degrees Minutes Seconds (DMS)</li><li>Degrees Decimal Minutes (DDM)</li><li>Decimal Degrees (DD)</li><li>Geohash</li><li>Military Grid Reference System (MGRS)</li><li>Ordnance Survey National Grid (OSNG)</li><li>Universal Transverse Mercator (UTM)</li></ul><br>This operation will not work offline.";
+        this.description = "Displays co-ordinates on a slippy map.<br><br>Co-ordinates will be converted to decimal degrees before being shown on the map.<br><br>Supported formats:<ul><li>Degrees Minutes Seconds (DMS)</li><li>Degrees Decimal Minutes (DDM)</li><li>Decimal Degrees (DD)</li><li>Geohash</li><li>Military Grid Reference System (MGRS)</li><li>Ordnance Survey National Grid (OSNG)</li><li>Universal Transverse Mercator (UTM)</li></ul><br>This operation will not work offline.";
         this.infoURL = "";
         this.inputType = "string";
         this.outputType = "string";
@@ -81,34 +81,32 @@ class ShowOnMap extends Operation {
      * @returns {string}
      */
     async present(data, args) {
-        if (data.replace(/\s+/g, "") !== "") {
-            const zoomLevel = args[0];
-            const tileUrl = "https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png",
-                tileAttribution = "&copy; <a href=\"https://www.openstreetmap.org/copyright\">OpenStreetMap</a> contributors",
-                leafletUrl = "https://unpkg.com/[email protected]/dist/leaflet.js",
-                leafletCssUrl = "https://unpkg.com/[email protected]/dist/leaflet.css";
-            return `<link rel="stylesheet" href="${leafletCssUrl}" crossorigin=""/>
+        if (data.replace(/\s+/g, "") === "") {
+            data = "0, 0";
+        }
+        const zoomLevel = args[0];
+        const tileUrl = "https://maps.wikimedia.org/osm-intl/{z}/{x}/{y}.png",
+            tileAttribution = "<a href=\"https://wikimediafoundation.org/wiki/Maps_Terms_of_Use\">Wikimedia maps</a> | &copy; <a href=\"https://www.openstreetmap.org/copyright\">OpenStreetMap</a> contributors",
+            leafletUrl = "https://unpkg.com/[email protected]/dist/leaflet.js",
+            leafletCssUrl = "https://unpkg.com/[email protected]/dist/leaflet.css";
+        return `<link rel="stylesheet" href="${leafletCssUrl}" crossorigin=""/>
 <style>#output-html { white-space: normal; }</style>
 <div id="presentedMap" style="width: 100%; height: 100%;"></div>
 <script type="text/javascript">
-    var mapscript = document.createElement('script');
-    document.body.appendChild(mapscript);
-    mapscript.onload = function() {
-        var presentMap = L.map('presentedMap').setView([${data}], ${zoomLevel});
-        L.tileLayer('${tileUrl}', {
-            attribution: '${tileAttribution}'
-        }).addTo(presentMap);
+var mapscript = document.createElement('script');
+document.body.appendChild(mapscript);
+mapscript.onload = function() {
+    var presentMap = L.map('presentedMap').setView([${data}], ${zoomLevel});
+    L.tileLayer('${tileUrl}', {
+        attribution: '${tileAttribution}'
+    }).addTo(presentMap);
 
-        L.marker([${data}]).addTo(presentMap)
-            .bindPopup('${data}')
-            .openPopup();
-    };
-    mapscript.src = "${leafletUrl}";
+    L.marker([${data}]).addTo(presentMap)
+        .bindPopup('${data}')
+        .openPopup();
+};
+mapscript.src = "${leafletUrl}";
 </script>`;
-        } else {
-            // Don't do anything if there's no input
-            return "";
-        }
     }
 }