/// <summary>
/// If the a ship's bearing to a given position is less than 90 degrees away from exact heading needed to get to the port,
/// Then we says that a ship is moving toward that port
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <param name="position">Location of port that ship may be moving toward</param>
/// <returns>true or false</returns>
public static bool IsMovingToward(this ShipTest shipTest, Position position)
{
var bearing = GeoHelper.GetBearing(shipTest.Position, position);
var difference = Math.Abs(shipTest.Heading - bearing);
return(difference <= 90);
}
/// <summary>
/// Does the ship's heading put it on course to enter Duluth Canal?
/// Ships report numerous false destinations. Therefore, we use this method
/// to check a ship's actual heading against the bearing to the two nearest ports
/// and make a determination whether or not the ship will actually use Duluth Canal
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsHeadingTowardDuluth(this ShipTest shipTest)
{
var twoNearestPortsAndBearing = Ports.All.Select(p => {
var bearing = GeoHelper.GetBearing(shipTest.Position, p);
var adjustment = Math.Abs(bearing - shipTest.Heading);
if (adjustment > 180)
{
adjustment = 360 - adjustment;
}
return(new {
Position = p,
Bearing = bearing,
Adjustment = adjustment
});
}).OrderBy(
p => p.Adjustment
).Take(2).ToArray();
var firstPort = twoNearestPortsAndBearing[0];
var secondPort = twoNearestPortsAndBearing[1];
var portBearingDiff = Math.Abs(firstPort.Bearing - secondPort.Bearing);
var weight = 1 / 2D;
if (shipTest.Destination == firstPort.Position)
{
weight = 2 / 3D;
}
else if (shipTest.Destination == secondPort.Position)
{
weight = 1 / 3D;
}
var threshold = weight * portBearingDiff;
Position nearestPort = null;
if (firstPort.Adjustment <= threshold)
{
nearestPort = firstPort.Position;
}
else if (secondPort.Adjustment <= threshold)
{
nearestPort = secondPort.Position;
}
else if (shipTest.IsMovingToward(firstPort.Position))
{
nearestPort = firstPort.Position;
}
return(nearestPort == Ports.Duluth);
}
/// <summary>
/// Method to populate a derived Eta for ships we deem will use Duluth Canal
/// </summary>
/// <param name="shipTest">ship test permutation</param>
public static void Update(this ShipTest shipTest)
{
var inHarbor = shipTest.IsInDuluthSuperiorHarbor();
if (inHarbor && !shipTest.CanalEntryTimestamp.HasValue)
{
shipTest.CanalEntryTimestamp = DateTime.UtcNow.AddHours(CanalEntryTimestampOffset);
}
else if (!inHarbor)
{
shipTest.CanalEntryTimestamp = null;
}
if (shipTest.IsUnderway())
{
if (shipTest.IsWithinFiftyMilesOfDuluth())
{
if (shipTest.IsInDuluthSuperiorHarborForMoreThanHour())
{
if (shipTest.IsInStLouisBay())
{
shipTest.DerivedEta = CalculateEtaToDuluthFromStLouisBay(shipTest.Position, shipTest.Speed);
}
else if (shipTest.IsMovingTowardDuluth())
{
shipTest.DerivedEta = CalculateEtaToDuluth(shipTest.Position, shipTest.Speed);
}
}
else if (!inHarbor && shipTest.IsHeadingTowardDuluth())
{
shipTest.DerivedEta = CalculateEtaToDuluth(shipTest.Position, shipTest.Speed);
}
}
else if (shipTest.IsDestinationDuluth() && shipTest.IsMovingTowardDuluth())
{
shipTest.DerivedEta = shipTest.Eta;
}
}
}
/// <summary>
/// Evaluation method and logic. Similar to shipTest Processor logic
/// First, only evaluate ship that report navigational status == underway
/// Next, ask if ship is within 50 miles of the Duluth Harbor
/// Locate ship inside or outside harbor
/// For ships in the harbor, treat ships in St. Louis Bay differently than other ships
/// For ships outside the harbor, populate derived eta according to bearing to nearest port
/// </summary>
/// <param name="shipTest">shipTest object</param>
public static void Evaluate(ShipTest shipTest)
{
if (shipTest.IsUnderway())
{
if (shipTest.IsWithinFiftyMilesOfDuluth())
{
if (shipTest.IsInDuluthSuperiorHarborForMoreThanHour())
{
shipTest.Evaluation = shipTest.IsInStLouisBay() || shipTest.IsMovingTowardDuluth();
}
else
{
shipTest.Evaluation = !shipTest.IsInDuluthSuperiorHarbor() && shipTest.IsHeadingTowardDuluth();
}
}
else
{
shipTest.Evaluation = shipTest.IsDestinationDuluth() && shipTest.IsMovingTowardDuluth();
}
}
shipTest.Evaluation = shipTest.Evaluation == shipTest.DerivedEta.HasValue;
shipTest.Tally = Convert.ToInt32(shipTest.Evaluation);
}
/// <summary>
/// Has a ship been in the Duluth Superior Harbor for more than an hour?
/// Reasoning: We use this test because ships have a variety of movements inside the harbor.
/// If a ship has entered the harbor recently, we're going to ignore its movements for a certain length of time
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsInDuluthSuperiorHarborForMoreThanHour(this ShipTest shipTest)
{
return(shipTest.CanalEntryTimestamp.HasValue && shipTest.CanalEntryTimestamp < DateTime.UtcNow.AddHours(-1));
}
/// <summary>
/// If the a ship's bearing to a given position is less than 90 degrees away from exact heading needed to get to the port,
/// Then we says that a ship is moving toward that port
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsMovingTowardDuluth(this ShipTest shipTest)
{
return(shipTest.IsMovingToward(Ports.Duluth));
}
/// <summary>
/// Is a ship reporting a destination of Duluth?
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsDestinationDuluth(this ShipTest shipTest)
{
return(shipTest.Destination == Ports.Duluth);
}
/// <summary>
/// Is a ship within 50 miles of the Duluth Canal?
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsWithinFiftyMilesOfDuluth(this ShipTest shipTest)
{
return(GeoHelper.DistanceBetweenCoord(shipTest.Position, Ports.Duluth) <= 50);
}
/// <summary>
/// Does the ship's reported navigational status contain the string "underway"?
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsUnderway(this ShipTest shipTest)
{
return(shipTest.NavigationalStatus == NavigationalStatus.Underway);
}
/// <summary>
/// Is a ship located in St. Louis Bay?
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsInStLouisBay(this ShipTest shipTest)
{
return(GeoHelper.IsPointInPolygon(shipTest.Position, Areas.StLouisBay));
}
/// <summary>
/// Uses point in polygon test to determine if a ship is located in the Duluth Superior Harbor
/// </summary>
/// <param name="shipTest">shipTest object</param>
/// <returns>true or false</returns>
public static bool IsInDuluthSuperiorHarbor(this ShipTest shipTest)
{
return(GeoHelper.IsPointInPolygon(shipTest.Position, Areas.DuluthSuperiorHarbor));
}