Use Double.NaN to indicate that a Helium gateway does not send altitude

ttnhabbridge/src/main/java/nl/sikken/bertrik/hab/habitat/docs/ListenerTelemetryDoc.java

@@ -33,7 +33,9 @@ public final class ListenerTelemetryDoc extends ListenerDoc {
         node.set("callsign", factory().textNode(receiver.getCallsign()));
         node.set("latitude", factory().numberNode(receiver.getLocation().getLat()));
         node.set("longitude", factory().numberNode(receiver.getLocation().getLon()));
-        node.set("altitude", factory().numberNode(receiver.getLocation().getAlt()));
+        if (Double.isFinite(receiver.getLocation().getAlt())) {
+            node.set("altitude", factory().numberNode(receiver.getLocation().getAlt()));
+        }
         return node;
     }
 

ttnhabbridge/src/main/java/nl/sikken/bertrik/hab/lorawan/HeliumUplinkMessage.java

@@ -55,7 +55,7 @@ public final class HeliumUplinkMessage {
         LoraWanUplinkMessage uplink = new LoraWanUplinkMessage(Instant.ofEpochMilli(reportedAt), appEui, name, fcnt,
                 port, payload);
         for (HotSpot hotSpot : hotSpots) {
-            uplink.addGateway(hotSpot.name.trim(), hotSpot.latitude, hotSpot.longitude, 0.0);
+            uplink.addGateway(hotSpot.name.trim(), hotSpot.latitude, hotSpot.longitude, Double.NaN);
         }
         return uplink;
     }

ttnhabbridge/src/test/java/nl/sikken/bertrik/hab/lorawan/HeliumUplinkMessageTest.java

@@ -10,6 +10,7 @@ import org.junit.Test;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 import nl.sikken.bertrik.hab.lorawan.HeliumUplinkMessage.HotSpot;
+import nl.sikken.bertrik.hab.lorawan.LoraWanUplinkMessage.GatewayInfo;
 
 public final class HeliumUplinkMessageTest {
 
@@ -46,6 +47,10 @@ public final class HeliumUplinkMessageTest {
         Assert.assertEquals(0, lorawan.getFcnt());
         Assert.assertEquals(1, lorawan.getPort());
         Assert.assertArrayEquals(new byte[] {3}, lorawan.getPayloadRaw());
+        GatewayInfo gw = lorawan.getGateways().get(0);
+        Assert.assertEquals(52.01745, gw.getLocation().getLat(), 0.00001);
+        Assert.assertEquals(4.729876, gw.getLocation().getLon(), 0.00001);
+        Assert.assertFalse(Double.isFinite(gw.getLocation().getAlt()));
     }
 
 }