Show a warning instead of an empty canvas if the ionosonde station has no data, and also show a warning if we have data but it's old.

webassets/apidocs/openapi.yml

@@ -1691,9 +1691,8 @@ components:
           type: object
           nullable: true
           description: >
-            Ionosonde measurements from the GIRO Data Center, keyed by URSI station code. Only
-            stations for which data was successfully retrieved are included. Null if the
-            GIROIonosonde provider has not yet completed its first poll or if this data source is disabled.
+            Ionosonde measurements from the GIRO Data Center, keyed by URSI station code. All known stations are
+            included, but not all of them may contain data.
           additionalProperties:
             $ref: '#/components/schemas/IonosondeStation'
 
@@ -1712,7 +1711,7 @@ components:
         fof2:
           type: object
           nullable: true
-          description: F2 layer critical frequency (foF2) measurements in MHz, keyed by UNIX timestamp (UTC seconds since epoch) of each measurement.
+          description: F2 layer critical frequency (foF2) measurements in MHz, keyed by UNIX timestamp (UTC seconds since epoch) of each measurement. Can be null if there is no data.
           additionalProperties:
             type: number
           example:
@@ -1721,7 +1720,7 @@ components:
         muf:
           type: object
           nullable: true
-          description: Maximum Usable Frequency (MUF) for a 3000 km path in MHz, keyed by UNIX timestamp (UTC seconds since epoch) of each measurement.
+          description: Maximum Usable Frequency (MUF) for a 3000 km path in MHz, keyed by UNIX timestamp (UTC seconds since epoch) of each measurement. Can be null if there is no data.
           additionalProperties:
             type: number
           example:

webassets/js/conditions.js

@@ -380,7 +380,9 @@ function populateIonosondeDropdown(data) {
 // Render the foF2/MUF data and line chart for the currently selected station
 function renderIonosondeData() {
     // First make sure that we have some data, that a station entry is selected in the drop-down box, and that the
-    // data contains an entry for that station. If not, bail out at this point.
+    // data contains an entry for that station. If not, this represents an odd state (over and above just "no data for
+    // this station", so bail out at this point. The user will have to reselect something from the list, or wait until
+    // the API is behaving itself again.
     if (!ionosondeData) return;
     const ursi = $('#ionosonde-station').val();
     if (!ursi) return;
@@ -406,7 +408,12 @@ function renderIonosondeData() {
     const fof2Entries = toSeries(station.fof2);
     const mufEntries = toSeries(station.muf);
     const allTs = [...fof2Entries, ...mufEntries].map(e => e.ts);
-    if (allTs.length === 0) return;
+    if (allTs.length === 0) {
+        $('#ionosonde-latest').html('<div class="alert alert-warning mt-2 mb-0 py-2">No data available for this station.</div>');
+        $('#ionosonde-chart').hide();
+        if (ionosondeChart) { ionosondeChart.destroy(); ionosondeChart = null; }
+        return;
+    }
 
     // Populate latest values summary (visible on all screen sizes)
     const latestFof2 = fof2Entries.length ? fof2Entries[fof2Entries.length - 1].val : null;
@@ -418,12 +425,16 @@ function renderIonosondeData() {
         const latestDate = moment.utc(maxTs * 1000);
         latestTimeStr = latestDate.format('DD MMM YYYY HH:mm [UTC]') + ' (' + latestDate.fromNow() + ')';
     }
+    const staleWarning = (maxTs !== null && (Date.now() / 1000 - maxTs) > 12 * 3600)
+        ? '<div class="alert alert-warning mt-2 mb-0 py-2">Data is more than 12 hours old!</div>'
+        : '';
     $('#ionosonde-latest').html(
         '<div class="row border-bottom align-items-center me-0">' +
         '<div class="col-12 col-md-6 py-2 text-muted">Latest values as of ' + latestTimeStr + '</div>' +
         '<div class="col-12 col-md-2 py-2">foF2: <strong>' + (latestFof2 !== null ? latestFof2.toFixed(2) + ' MHz' : 'N/A') + '</strong></div>' +
         '<div class="col-12 col-md-4 py-2">MUF (3000 km): <strong>' + (latestMuf !== null ? latestMuf.toFixed(2) + ' MHz' : 'N/A') + '</strong></div>' +
         '</div>' +
+        staleWarning +
         '</div>'
     );
 
@@ -564,6 +575,9 @@ function renderIonosondeData() {
         },
         plugins: [bandLinesPlugin],
     });
+
+    // Chart canvas is normally hidden until we get here with some definitely good data. Now we have that so show it
+    $('#ionosonde-chart').show();
 }
 
 // Called when the ionosonde station select changes