/// <summary>
/// todo use threads and threadData
/// </summary>
/// <param name="points"></param>
/// <param name="input"></param>
public GridCluster(IList<MapPoint> points, MarkersInput input)
: base(points)
{
this._input = input;
double[] deltas = GetDelta(GmcSettings.Get.GridX, GmcSettings.Get.GridY, input.Zoomlevel);
DeltaX = deltas[0];
DeltaY = deltas[1];
Grid = GetBoundaryExtended(input);
}
public static Boundary GetBoundaryExtended(MarkersInput input)
{
var deltas = GetDelta(GmcSettings.Get.GridX, GmcSettings.Get.GridY, input.Zoomlevel);
var deltaX = deltas[0];
var deltaY = deltas[1];
// Grid with extended outer grid-area non-visible
var a = MathTool.FloorLatLon(input.Viewport.MinX, deltaX) - deltaX * GmcSettings.Get.OuterGridExtend;
var b = MathTool.FloorLatLon(input.Viewport.MinY, deltaY) - deltaY * GmcSettings.Get.OuterGridExtend;
var a2 = MathTool.FloorLatLon(input.Viewport.MaxX, deltaX) + deltaX * (1 + GmcSettings.Get.OuterGridExtend);
var b2 = MathTool.FloorLatLon(input.Viewport.MaxY, deltaY) + deltaY * (1 + GmcSettings.Get.OuterGridExtend);
// Latitude is special with Google Maps, they don't wrap around, then do constrain
b = MathTool.ConstrainLatitude(b);
b2 = MathTool.ConstrainLatitude(b2);
var grid = new Boundary { MinX = a, MinY = b, MaxX = a2, MaxY = b2 };
grid.Normalize();
return grid;
}
/// <summary>
/// Read Through Cache
/// </summary>
/// <param name="getParams"></param>
/// <returns></returns>
private ClusterMarkersResponse GetMarkersHelper(GetMarkersParams getParams)
{
try
{
var neLat = getParams.NorthEastLatitude;
var neLong = getParams.NorthEastLongitude;
var swLat = getParams.SouthWestLatitude;
var swLong = getParams.SouthWestLongitude;
var zoomLevel = getParams.ZoomLevel;
var filter = getParams.Filter ?? "";
// values are validated there
var markersInput = new MarkersInput(neLat, neLong, swLat, swLong, zoomLevel, filter);
var grid = GridCluster.GetBoundaryExtended(markersInput);
var cacheKeyHelper = string.Format("{0}_{1}_{2}", markersInput.Zoomlevel, markersInput.FilterHashCode(), grid.GetHashCode());
var cacheKey = CacheKeys.GetMarkers(cacheKeyHelper.GetHashCode());
var response = new ClusterMarkersResponse();
markersInput.Viewport.ValidateLatLon(); // Validate google map viewport input (should be always valid)
markersInput.Viewport.Normalize();
// Get all points from memory
IList<MapPoint> points = _pointCollection.Get(getParams.PointType); // _pointsDatabase.GetPoints();
// Filter points
points = FilterUtil.FilterByType(
points,
new FilterData { TypeFilterExclude = markersInput.TypeFilterExclude }
);
// Create new instance for every ajax request with input all points and json data
var clusterAlgo = new GridCluster(points, markersInput);
var clusteringEnabled = markersInput.IsClusteringEnabled
|| GmcSettings.Get.AlwaysClusteringEnabledWhenZoomLevelLess > markersInput.Zoomlevel;
// Clustering
if (clusteringEnabled && markersInput.Zoomlevel < GmcSettings.Get.ZoomlevelClusterStop)
{
IList<MapPoint> markers = clusterAlgo.RunCluster();
response = new ClusterMarkersResponse
{
Markers = markers,
Polylines = clusterAlgo.GetPolyLines()
};
}
else
{
// If we are here then there are no clustering
// The number of items returned is restricted to avoid json data overflow
IList<MapPoint> filteredDataset = FilterUtil.FilterDataByViewport(points, markersInput.Viewport);
IList<MapPoint> filteredDatasetMaxPoints = filteredDataset.Take(GmcSettings.Get.MaxMarkersReturned).ToList();
response = new ClusterMarkersResponse
{
Markers = filteredDatasetMaxPoints,
Polylines = clusterAlgo.GetPolyLines(),
Mia = filteredDataset.Count - filteredDatasetMaxPoints.Count,
};
}
// if client ne and sw is inside a specific grid box then cache the grid box and the result
// next time test if ne and sw is inside the grid box and return the cached result
if (GmcSettings.Get.CacheServices)
_memCache.Set(cacheKey, response, TimeSpan.FromMinutes(10)); // cache data
return response;
}
catch (Exception ex)
{
return new ClusterMarkersResponse
{
OperationResult = "0",
ErrorMessage = string.Format("MapService says: exception {0}", ex.Message)
};
}
}