public async Task <double> GetElevation(double lat, double lng)
{
IElevationService service = GetService();
if (service is RandomElevationService)
{
// Don't hit the database for random elevation service.
return(await service.GetElevation(lat, lng).ConfigureAwait(false));
}
ElevationLocation elevationLocation = await ElevationLocation.FindOrUpdateInDatabase(_context, lat, lng, service).ConfigureAwait(false);
if (elevationLocation == null)
{
Logger.Write(
$"{service.GetServiceId()} response not reliable and will be blacklisted for one hour.",
LogLevel.Warning
);
BlacklistStrategy(service.GetType());
Logger.Write(
$"Falling back to next elevation strategy: {GetService().GetServiceId()}.",
LogLevel.Warning
);
// After blacklisting, retry.
return(await service.GetElevation(lat, lng).ConfigureAwait(false));
}
return(BaseElevationService.GetRandomElevation(elevationLocation.Altitude));
}
public double GetElevation(double lat, double lng)
{
IElevationService service = GetService();
double elevation = service.GetElevation(lat, lng);
if (elevation == 0 || elevation < -100)
{
// Error getting elevation so just return 0.
Logger.Write(
$"{service.GetServiceId()} response not reliable: {elevation.ToString()}, and will be blacklisted for one hour.",
LogLevel.Warning
);
BlacklistStrategy(service.GetType());
Logger.Write(
$"Falling back to next elevation strategy: {GetService().GetServiceId()}.",
LogLevel.Warning
);
// After blacklisting, retry.
return(GetElevation(lat, lng));
}
return(elevation);
}
public static async Task <ElevationLocation> FindOrUpdateInDatabase(double latitude, double longitude, IElevationService service)
{
using (await DB_LOCK.LockAsync().ConfigureAwait(false))
{
if (!Directory.Exists(CACHE_DIR))
{
Directory.CreateDirectory(CACHE_DIR);
}
LiteEngine.Upgrade(DB_NAME, null, true);
using (var db = new LiteDatabase(DB_NAME))
{
db.GetCollection <ElevationLocation>("locations").EnsureIndex(s => s.Id);
var locationsCollection = db.GetCollection <ElevationLocation>("locations");
var id = GetIdTokenFromLatLng(latitude, longitude);
var elevationLocation = locationsCollection.FindOne(x => x.Id == id);
if (elevationLocation != null)
{
return(elevationLocation);
}
for (var i = 0; i < MAX_RETRIES; i++)
{
try
{
var altitude = await service.GetElevation(latitude, longitude).ConfigureAwait(false);
if (altitude == 0 || altitude < -100)
{
// Invalid altitude
return(null);
}
elevationLocation = new ElevationLocation(latitude, longitude)
{
Altitude = altitude
};
locationsCollection.Insert(elevationLocation);
return(elevationLocation);
}
catch (Exception)
{
// Just ignore exception and retry after delay
await Task.Delay(i * 100).ConfigureAwait(false);
}
}
return(null);
}
}
}
public static async Task <double> getElevation(IElevationService elevationService, double lat, double lon)
{
if (elevationService != null)
{
return(await elevationService.GetElevation(lat, lon).ConfigureAwait(false));
}
Random random = new Random();
double maximum = 11.0f;
double minimum = 8.6f;
double return1 = random.NextDouble() * (maximum - minimum) + minimum;
return(return1);
}
public static double getElevation(IElevationService elevationService, double lat, double lon)
{
if (elevationService != null)
{
return(elevationService.GetElevation(lat, lon));
}
Random random = new Random();
double maximum = 11.0f;
double minimum = 8.6f;
double return1 = random.NextDouble() * (maximum - minimum) + minimum;
return(return1);
}
public static async Task <ElevationLocation> FindOrUpdateInDatabase(ElevationConfigContext db, double latitude, double longitude, IElevationService service)
{
latitude = Math.Round(latitude, GEOLOCATION_PRECISION);
longitude = Math.Round(longitude, GEOLOCATION_PRECISION);
var elevationLocation = db.ElevationLocation.FirstOrDefault(x => x.Latitude == latitude && x.Longitude == longitude);
if (elevationLocation != null)
{
return(elevationLocation);
}
for (var i = 0; i < MAX_RETRIES; i++)
{
try
{
var altitude = await service.GetElevation(latitude, longitude).ConfigureAwait(false);
if (altitude == 0 || altitude < -100)
{
// Invalid altitude
return(null);
}
db.ElevationLocation.Add(new ElevationLocation(latitude, longitude)
{
Altitude = altitude
});
await db.SaveChangesAsync().ConfigureAwait(false);
return(elevationLocation);
}
catch (Exception)
{
// Just ignore exception and retry after delay
await Task.Delay(i * 100).ConfigureAwait(false);
}
}
return(null);
}
