Display distance and time info for wind/skew-t sources

lib/area.dart

@@ -38,7 +38,7 @@ class Area {
     // get surface wind from nearest airport
     String wind = WindsCache.getWind0kFromMetar(Gps.toLatLng(position));
     // get aloft wind from nearest station
-    String? station = WindsCache.locateNearestStation(Gps.toLatLng(position));
+    var (station, dist, bearing) = WindsCache.locateNearestStation(Gps.toLatLng(position));
     WindsAloft? wa = Storage().winds.get("${station}06H") as WindsAloft?;
     if(null != wa) {
       // combine surface and aloft wind
@@ -55,4 +55,4 @@ class Area {
     }
     return (direction, speed);
   }
-}
+}

lib/geo_calculations.dart

@@ -72,27 +72,27 @@ class GeoCalculations {
     String dir;
     double bearing = getMagneticHeading(bearingIn, declination);
     if ((bearing > dirDegrees) && (bearing <= (90 - dirDegrees))) {
-      dir = "SW of";
+      dir = "SW";
     } else {
       if ((bearing > (90 - dirDegrees)) && (bearing <= (90 + dirDegrees))) {
-        dir = "W of";
+        dir = "W";
       } else {
         if ((bearing > (90 + dirDegrees)) && (bearing <= (180 - dirDegrees))) {
-          dir = "NW of";
+          dir = "NW";
         } else {
           if ((bearing > (180 - dirDegrees)) && (bearing <= (180 + dirDegrees))) {
-            dir = "N of";
+            dir = "N";
           } else {
             if ((bearing > (180 + dirDegrees)) && (bearing <= (270 - dirDegrees))) {
-              dir = "NE of";
+              dir = "NE";
             } else {
               if ((bearing > (270 - dirDegrees)) && (bearing <= (270 + dirDegrees))) {
-                dir = "E of";
+                dir = "E";
               } else {
                 if ((bearing > (270 + dirDegrees)) && (bearing <= (360 - dirDegrees))) {
-                  dir = "SE of";
+                  dir = "SE";
                 } else {
-                  dir = "S of";
+                  dir = "S";
                 }
               }
             }

lib/longpress_screen.dart

@@ -96,7 +96,7 @@ class LongPressScreenState extends State<LongPressScreen> {
     LatLng ll = LatLng(Storage().position.latitude, Storage().position.longitude);
     double distance = geo.calculateDistance(ll, widget.destinations[0].coordinate);
     double bearing = geo.calculateBearing(ll, widget.destinations[0].coordinate);
-    String direction = ("${distance.round()} ${GeoCalculations.getGeneralDirectionFrom(bearing, Storage().area.variation)}");
+    String direction = ("${distance.round()} ${Storage().units.distanceName} ${GeoCalculations.getGeneralDirectionFrom(bearing, Storage().area.variation)}");
     String facility = showDestination.facilityName.length > 16 ? showDestination.facilityName.substring(0, 16) : showDestination.facilityName;
     List<Widget?> pages = List.generate(labels.length, (index) => null);
     String label = "$facility (${showDestination.locationID}) $direction${showDestination.elevation != null ? "; EL ${showDestination.elevation!.round()}" : ""}";
@@ -123,7 +123,7 @@ class LongPressScreenState extends State<LongPressScreen> {
         ]);
       }
       pages[labels.indexOf("NOTAM")] = FutureBuilder(future: Storage().notam.getSync(showDestination.locationID),
-        builder: (context, snapshot) { // notmas are downloaded when not in cache and can be slow to download so do async
+        builder: (context, snapshot) { // notams are downloaded when not in cache and can be slow to download so do async
           if (snapshot.hasData) {
             return snapshot.data != null ?
               SingleChildScrollView(child: Padding(padding: const EdgeInsets.all(10), child:Text((snapshot.data as Notam).text)))
@@ -159,13 +159,13 @@ class LongPressScreenState extends State<LongPressScreen> {
     }
 
     Weather? winds;
-    String? station = WindsCache.locateNearestStation(showDestination.coordinate);
+    var (station, dist, stationBearing) = WindsCache.locateNearestStation(showDestination.coordinate);
     if(station != null) {
       winds = Storage().winds.get("${station}06H"); // 6HR wind
       if(winds != null) {
         WindsAloft wa = winds as WindsAloft;
         pages[labels.indexOf("Wind")] = ListView(children: [
-          ListTile(title: Text(winds.toString())),
+          ListTile(title: Text('${dist.round()} ${Storage().units.distanceName} ${GeoCalculations.getGeneralDirectionFrom(stationBearing, 0)} @ ${winds.toString()}')),
           for((String, String) wl in wa.toList())
             ListTile(leading: Text(wl.$1), title: Text(wl.$2)),
         ]);

lib/time_zone.dart

@@ -0,0 +1,25 @@
+
+class TimeZone {
+  //calculates the timestamp from the passed Zulu time in METAR format (e.g. DDHHMMZ)
+  //any trailing values after the Z are disregarded
+  //if there isn't 7 characters to create a Zulu time, or letters in first six locations, returns null
+  static DateTime? parseZuluTime(String s)
+  {
+    if(s.length < 7 || int.tryParse(s.substring(0,5)) == null)
+    {
+      return null;
+    }
+    DateTime now = DateTime.now().toUtc();
+    DateTime expires = DateTime.utc(
+        now.year,
+        now.month,
+        now.day, //day
+        0,
+        0);
+    int from = int.parse(s[2]!);
+    int to = int.parse(s[3]!);
+    // if from > to then its next day
+    expires = expires.add(Duration(days: to < from ? 1 : 0, hours: int.parse(s[3]!.substring(0, 2)), minutes: int.parse(s[5]!.substring(0, 2))));
+    return expires;
+  }
+}

lib/unit_conversion.dart

@@ -8,6 +8,7 @@ class UnitConversion {
       mpsTo = 2.23694;
       toMps = 0.44704;
       knotsTo = 1.15078;
+      distanceName = 'mi';
     }
   }
 
@@ -28,4 +29,7 @@ class UnitConversion {
   // knots for wind.
   double knotsTo = 1;
 
-}
+  //name of distance unit
+  String distanceName = 'nm';
+
+}

lib/weather/sounding.dart

@@ -7,20 +7,27 @@ import '../geo_calculations.dart';
 
 class Sounding {
 
-  static String? _locateNearestStation(LatLng location) {
+  static (String?, double, double) _locateNearestStation(LatLng location) {
 
     // find distance
     GeoCalculations geo = GeoCalculations();
     double distanceMin = double.maxFinite;
     String? station;
+    LatLng? stationLocation;
     for(MapEntry<String, LatLng> map in _stationMap.entries) {
       double distance = geo.calculateDistance(map.value, location);
       if(distance < distanceMin) {
         distanceMin = distance;
         station = map.key;
+        stationLocation = map.value;
       }
     }
-    return station;
+    double? bearing;
+    if(stationLocation != null)
+    {
+      bearing = geo.calculateBearing(stationLocation, location);
+    }
+    return (station, distanceMin, bearing ?? 0);
   }
 
   static Widget? getSoundingImage(LatLng coordinate, BuildContext context) {
@@ -29,20 +36,35 @@ class Sounding {
       return const Center(child: Text('Error downloading the Sounding Analysis for this area.'));
     }
 
-    String? station = _locateNearestStation(coordinate);
+    var (station, dist, bearing) = _locateNearestStation(coordinate);
     if(null == station) {
       return null;
     }
-    DateTime now = DateTime.now().toUtc();
+    DateTime now = DateTime.timestamp();
     now = now.subtract(const Duration(hours: 1)); // 1 hour delayed on website
-    String hour = ((now.hour / 12).floor() * 12).toString().padLeft(2, '0');
-    String year = now.year.toString().substring(2);
-    String day = now.day.toString().padLeft(2, '0');
-    String month = now.month.toString().padLeft(2, '0');
+    DateTime obsTime = DateTime.utc(now.year, now.month, now.day,  (now.hour/ 12).floor() * 12);
+    String hour = obsTime.hour.toString().padLeft(2, '0');
+    String year = obsTime.year.toString().substring(2);
+    String day = obsTime.day.toString().padLeft(2, '0');
+    String month = obsTime.month.toString().padLeft(2, '0');
     String url = "https://www.spc.noaa.gov/exper/soundings/$year$month$day${hour}_OBS/$station.gif";
+    Duration timeSinceObs = DateTime.timestamp().difference(obsTime);
     CachedNetworkImage image = CachedNetworkImage(imageUrl: url, cacheManager: FileCacheManager().networkCacheManager, errorWidget: errorImage,);
-    return Container(padding: const EdgeInsets.all(10), child:
-      InteractiveViewer(child: Container(color: Colors.white , alignment: Alignment.center, child: image)));
+    return ListView(
+      children: <Widget>[
+        ListTile(title: Text("${dist.round()} ${Storage().units.distanceName} ${GeoCalculations.getGeneralDirectionFrom(bearing, 0)} @ ${station} (${timeSinceObs.inHours}:${(timeSinceObs.inMinutes % 60).toString().padLeft(2, '0')} ago)")),
+        Container(
+          padding: const EdgeInsets.symmetric(horizontal: 10),
+          child: InteractiveViewer(
+            child: Container(
+              color: Colors.white,
+              alignment: Alignment.center,
+              child: image
+            )
+          )
+        )
+      ]
+    );
   }
 
   // List of station codes from the HTML area elements

lib/weather/winds_aloft.dart

@@ -47,6 +47,10 @@ class WindsAloft extends Weather {
     return(dir, (speed.toDouble() * Storage().units.knotsTo).round());
   }
 
+  static String invertTemperature(String wind) {
+    return wind.replaceRange(4,4,'-');
+  }
+
   (double?, double?) getWindAtAltitude(double altitude) { // dir, speed
     String wHigher;
     String wLower;
@@ -176,13 +180,13 @@ class WindsAloft extends Weather {
       return w24k;
     }
     else if (altitude == 30000) {
-      return w30k;
+      return invertTemperature(w30k);
     }
     else if (altitude == 34000) {
-      return w34k;
+      return invertTemperature(w34k);
     }
     else if (altitude == 39000) {
-      return w39k;
+      return invertTemperature(w39k);
     }
     return "N/A";
   }
@@ -242,7 +246,7 @@ class WindsAloft extends Weather {
   toString() {
     DateTime zulu = expires.toUtc(); // winds in Zulu time
     // boilerplate
-    String wind = "$station (Temps negative above 24000)\nValid till ${zulu.day .toString().padLeft(2, "0")}${zulu.hour.toString().padLeft(2, "0")}00Z";
+    String wind = "$station\nValid till ${expires.hour.toString().padLeft(2, '0')}:${expires.minute.toString().padLeft(2, '0')} (${zulu.day.toString().padLeft(2, '0')}${zulu.hour.toString().padLeft(2, '0')}00Z)";
     return wind;
   }
 }

lib/weather/winds_cache.dart

@@ -3,6 +3,7 @@ import 'dart:typed_data';
 
 import 'package:avaremp/data/weather_database_helper.dart';
 import 'package:avaremp/geo_calculations.dart';
+import 'package:avaremp/time_zone.dart';
 import 'package:avaremp/storage.dart';
 import 'package:avaremp/weather/weather_cache.dart';
 import 'package:avaremp/weather/winds_aloft.dart';
@@ -34,7 +35,7 @@ class WindsCache extends WeatherCache {
     double? ws;
     double? wd;
     String foreString = fore.toString().padLeft(2, "0"); // stations has fore in the name
-    String? station = WindsCache.locateNearestStation(coordinate);
+    var (station, dist, bearing) = WindsCache.locateNearestStation(coordinate);
     var ww = Storage().winds.get("$station${foreString}H");
     (wd, ws) = WindsCache.getWindAtAltitude(altitude, ww == null ? null : ww as WindsAloft);
     return (wd, ws);
@@ -50,12 +51,22 @@ class WindsCache extends WeatherCache {
 
     for(Uint8List datum in data)
     {
+      RegExp exp1 = RegExp("VALID\\s*([0-9]*)Z\\s*FOR USE\\s*([0-9]*)-([0-9]*)Z");
       String dataString = utf8.decode(datum);
 
       // parse winds, set expire time 6 hrs in future
-      DateTime expires = DateTime.now().add(const Duration(hours: 6));
+      DateTime? expires;
       List<String> lines = dataString.split('\n');
 
+      for (String line in lines) {
+        line = line.trim();
+        RegExpMatch? match = exp1.firstMatch(line);
+        if (match != null) {
+          expires = TimeZone.parseZuluTime(match.toString());
+          break;
+        }
+      }
+
       bool start = false;
       // parse winds, first check if a new download is needed
       _WindsAloftProduct? p = _getWindsAloftProductType(lines);
@@ -70,6 +81,9 @@ class WindsCache extends WeatherCache {
         if(!start) {
           continue;
         }
+        if(expires == null) {
+          continue;
+        }
 
         // find fore in winds. Stations are suffixes with 06H 12H or 24H for 6 12 and 24 hour forecasts
         String fore = p.toString().substring(p.toString().length - 3);
@@ -184,19 +198,27 @@ class WindsCache extends WeatherCache {
     return null;
   }
 
-  static String? locateNearestStation(LatLng location) {
+  //returns station name, distance, bearing
+  static (String?, double, double) locateNearestStation(LatLng location) {
     // find distance
     GeoCalculations geo = GeoCalculations();
     double distanceMin = double.maxFinite;
     String? station;
+    LatLng? stationLocation;
     for(MapEntry<String, LatLng> map in _stationMap.entries) {
       double distance = geo.calculateDistance(map.value, location);
       if(distance < distanceMin) {
         distanceMin = distance;
         station = map.key;
+        stationLocation = map.value;
       }
     }
-    return station;
+    double? bearing;
+    if(stationLocation != null)
+    {
+      bearing = geo.calculateBearing(stationLocation, location);
+    }
+    return (station, distanceMin, bearing ?? 0);
   }
 
   // dir, speed