/// <summary>
/// Calculate the intersection point of two line segments
/// adapted to C# from http://rbrundritt.wordpress.com/2008/10/20/approximate-points-of-intersection-of-two-line-segments/
/// </summary>
/// <returns>Null if there is no intersection. Otherwise the point of intersection.</returns>
public static IGeoLocation SimplePolylineIntersection(IGeoLocation latlong1, IGeoLocation latlong2, IGeoLocation latlong3, IGeoLocation latlong4)
{
//Line segment 1 (p1, p2)
var a1 = latlong2.Latitude - latlong1.Latitude;
var b1 = latlong1.Longitude - latlong2.Longitude;
var c1 = a1 * latlong1.Longitude + b1 * latlong1.Latitude;
//Line segment 2 (p3, p4)
var a2 = latlong4.Latitude - latlong3.Latitude;
var b2 = latlong3.Longitude - latlong4.Longitude;
var c2 = a2 * latlong3.Longitude + b2 * latlong3.Latitude;
var determinate = a1 * b2 - a2 * b1;
IGeoLocation intersection;
if (determinate != 0)
{
var x = (b2 * c1 - b1 * c2) / determinate;
var y = (a1 * c2 - a2 * c1) / determinate;
var intersect = new GeoLocation(y, x);
if (InBoundedBox(latlong1, latlong2, intersect) && InBoundedBox(latlong3, latlong4, intersect))
intersection = intersect;
else
intersection = null;
}
else //lines are parallel
intersection = null;
return intersection;
}
/// <summary>
/// Stores employee trackpoints.
/// Used by the mobile phone application.
/// NOTE: TrackPoints CollectedTimeStamp should be in UTC.
/// </summary>
/// <param name="roleId">Current roleId </param>
/// <param name="trackPoints">The list of TrackPoints being passed from an Employee's device</param>
/// <returns>An Http response to the device signaling that the TrackPoint was successfully created</returns>
public void Post(Guid roleId, TrackPoint[] trackPoints)
{
if (!trackPoints.Any() || !trackPoints.First().RouteId.HasValue)
throw Request.BadRequest();
var routeId = trackPoints.First().RouteId.Value;
var currentUserAccount = CoreEntitiesContainer.CurrentUserAccount();
var currentBusinessAccount = CoreEntitiesContainer.Owner(roleId, new[] { RoleType.Administrator, RoleType.Regular, RoleType.Mobile }).FirstOrDefault();
//Return an Unauthorized Status Code if
//a) there is no UserAccount
//b) the user does not have access to the route (currentBusinessAccount == null)
if (currentUserAccount == null || currentBusinessAccount == null)
throw Request.NotAuthorized();
var employee = CoreEntitiesContainer.Employees.FirstOrDefault(e => e.LinkedUserAccount.Id == currentUserAccount.Id
&& e.EmployerId == currentBusinessAccount.Id);
if (employee == null)
throw Request.NotFound("Employee");
//order the new track points by their TimeStamps
//remove inaccurate trackpoints
var orderedModelTrackPoints = trackPoints.Where(tp => tp.Accuracy < 50).OrderBy(tp => tp.CollectedTimeStamp).ToArray();
var latestTrackPoint = orderedModelTrackPoints.LastOrDefault();
//if there was a previous point today, check the latest point is not erroneous
if (employee.LastTimeStamp.HasValue && DateTime.UtcNow.Subtract(employee.LastTimeStamp.Value) < TimeSpan.FromDays(1))
{
var previous = new GeoLocation(employee.LastLatitude.Value, employee.LastLongitude.Value);
latestTrackPoint = orderedModelTrackPoints.LastOrDefault(t => !Erroneous(t, previous, t.CollectedTimeStamp.Subtract(employee.LastTimeStamp.Value)));
//set the heading based on the previous point
if (latestTrackPoint != null)
latestTrackPoint.Heading = (int)GeoLocationTools.Bearing(previous, latestTrackPoint);
}
if (latestTrackPoint != null)
{
//Save the latest (most current) TrackPoint to the database
employee.LastCompassDirection = latestTrackPoint.Heading;
employee.LastLatitude = (double?)latestTrackPoint.Latitude;
employee.LastLongitude = (double?)latestTrackPoint.Longitude;
employee.LastSource = latestTrackPoint.Source;
employee.LastSpeed = (double?)latestTrackPoint.Speed;
employee.LastTimeStamp = latestTrackPoint.CollectedTimeStamp;
employee.LastAccuracy = latestTrackPoint.Accuracy;
}
//Push TrackPoints to Azure as long as either
//the LastPushToAzureTimeStamp is null
//the LastPushToAzureTimeStamp difference from the TrackPoint is > TimeBetweenPushesToAzure
var lastPushToAzureTimeStamp = employee.LastPushToAzureTimeStamp;
//send the TrackPoints to azure, that are seperated by TimeBetweenPushesToAzure (in seconds)
foreach (var trackPoint in orderedModelTrackPoints)
{
if (lastPushToAzureTimeStamp.HasValue && (trackPoint.CollectedTimeStamp - lastPushToAzureTimeStamp) < TimeSpan.FromSeconds(UpdateConstants.SecondsBetweenHistoricalTrackPoints))
continue;
if (trackPoint.Id == Guid.Empty)
trackPoint.Id = Guid.NewGuid();
PushTrackPointToAzure(currentBusinessAccount, trackPoint, employee, routeId);
lastPushToAzureTimeStamp = trackPoint.CollectedTimeStamp;
}
employee.LastPushToAzureTimeStamp = lastPushToAzureTimeStamp;
//Save all the changes that have been made in the Database
SaveWithRetry();
}
