public GridCluster(IPoints dataset, JsonGetMarkersReceive jsonReceive)
: base(dataset)
{
// Important, set _delta and _grid values in constructor as first step
var deltas = GetDelta(jsonReceive);
DeltaX = deltas[0];
DeltaY = deltas[1];
Grid = GetBoundaryExtended(jsonReceive);
Lines = new List<Line>();
if (AlgoConfig.DoShowGridLinesInGoogleMap) MakeLines(jsonReceive);
}
public static Boundary GetBoundaryExtended(JsonGetMarkersReceive jsonReceive)
{
var deltas = GetDelta(jsonReceive);
var deltaX = deltas[0];
var deltaY = deltas[1];
// Grid with extended outer grid-area non-visible
var a = MathTool.FloorLatLon(jsonReceive.Viewport.Minx, deltaX) - deltaX * AlgoConfig.OuterGridExtend;
var b = MathTool.FloorLatLon(jsonReceive.Viewport.Miny, deltaY) - deltaY * AlgoConfig.OuterGridExtend;
var a2 = MathTool.FloorLatLon(jsonReceive.Viewport.Maxx, deltaX) + deltaX * (1 + AlgoConfig.OuterGridExtend);
var b2 = MathTool.FloorLatLon(jsonReceive.Viewport.Maxy, deltaY) + deltaY * (1 + AlgoConfig.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;
}
public static double[] GetDelta(JsonGetMarkersReceive jsonReceive)
{
// Heuristic specific values and grid size dependent.
// used in combination with zoom level.
// xZoomLevel1 and yZoomLevel1 is used to define the size of one grid-cell
// Absolute base value of longitude distance
const int xZoomLevel1 = 480;
// Absolute base value of latitude distance
const int yZoomLevel1 = 240;
// Relative values, used for adjusting grid size
var gridScaleX = AlgoConfig.Gridx;
var gridScaleY = AlgoConfig.Gridy;
var x = MathTool.Half(xZoomLevel1, jsonReceive.Zoomlevel - 1) / gridScaleX;
var y = MathTool.Half(yZoomLevel1, jsonReceive.Zoomlevel - 1) / gridScaleY;
return new double[] { x, y };
}
void MakeLines(JsonGetMarkersReceive jsonReceive)
{
if(!jsonReceive.IsDebugLinesEnabled) return; // client disabled it
// Make the red lines data to be drawn in Google map
var temp = new List<Rectangle>();
const int borderLinesAdding = 1;
var linesStepsX = (int)(Math.Round(Grid.AbsX / DeltaX) + borderLinesAdding);
var linesStepsY = (int)(Math.Round(Grid.AbsY / DeltaY) + borderLinesAdding);
var b = new Boundary(Grid);
const double restrictLat = 5.5;
b.Miny = MathTool.ConstrainLatitude(b.Miny, restrictLat); // Make sure it is visible on screen, restrict by some value
b.Maxy = MathTool.ConstrainLatitude(b.Maxy, restrictLat);
// Vertical lines
for (var i = 0; i < linesStepsX; i++)
{
var xx = b.Minx + i * DeltaX;
// Draw region
if (jsonReceive.Zoomlevel > 3)
{
temp.Add(new Rectangle { Minx = xx, Miny = b.Miny, Maxx = xx, Maxy = b.Maxy });
}
// World wrap issue when same latlon area visible multiple times
// Make sure line is drawn from left to right on screen
else
{
temp.Add(new Rectangle { Minx = xx, Miny = LatLonInfo.MinLatValue + restrictLat, Maxx = xx, Maxy = 0 });
temp.Add(new Rectangle { Minx = xx, Miny = 0, Maxx = xx, Maxy = LatLonInfo.MaxLatValue-restrictLat });
}
}
// Horizontal lines
for (var i = 0; i < linesStepsY; i++)
{
var yy = b.Miny + i * DeltaY;
// Draw region
if (jsonReceive.Zoomlevel > 3)
{
// Don't draw lines outsize the world
if (MathTool.IsLowerThanLatMin(yy) || MathTool.IsGreaterThanLatMax(yy)) continue;
temp.Add(new Rectangle { Minx = b.Minx, Miny = yy, Maxx = b.Maxx, Maxy = yy });
}
// World wrap issue when same latlon area visible multiple times
// Make sure line is drawn from left to right on screen
else
{
temp.Add(new Rectangle { Minx = LatLonInfo.MinLonValue, Miny = yy, Maxx = 0, Maxy = yy });
temp.Add(new Rectangle { Minx = 0, Miny = yy, Maxx = LatLonInfo.MaxLonValue, Maxy = yy });
}
}
// Normalize the lines and add as string
foreach (var line in temp)
{
var x = (line.Minx).NormalizeLongitude().DoubleToString();
var x2 = (line.Maxx).NormalizeLongitude().DoubleToString();
var y = (line.Miny).NormalizeLatitude().DoubleToString();
var y2 = (line.Maxy).NormalizeLatitude().DoubleToString();
Lines.Add(new Line { X = x, Y = y, X2 = x2, Y2 = y2 });
}
}
// Post
public JsonMarkersReply Markers(
double nelat, double nelon, double swlat, double swlon,
int zoomlevel, string filter, int sendid
)
{
var sw = new Stopwatch();
sw.Start();
var jsonReceive = new JsonGetMarkersReceive(nelat, nelon, swlat, swlon, zoomlevel, filter, sendid);
var clusteringEnabled = jsonReceive.IsClusteringEnabled || AlgoConfig.AlwaysClusteringEnabledWhenZoomLevelLess > jsonReceive.Zoomlevel;
JsonMarkersReply reply;
jsonReceive.Viewport.ValidateLatLon(); // Validate google map viewport input (is always valid)
jsonReceive.Viewport.Normalize();
// Get all points from memory
IPoints points = MemoryDatabase.GetPoints();
if (jsonReceive.TypeFilterExclude.Count == AlgoConfig.MarkerTypes.Count)
{
// Filter all
points = new Points(); // empty
}
else if (jsonReceive.TypeFilterExclude.Count > 0)
{
// Filter data by typeFilter value
// Make new obj, don't overwrite obj data
points = new Points
{
Data = points.Data
.Where(p => jsonReceive.TypeFilterExclude.Contains(p.T) == false)
.ToList()
};
}
// Create new instance for every ajax request with input all points and json data
var clusterAlgo = new GridCluster(points, jsonReceive); // create polylines
// Clustering
if (clusteringEnabled && jsonReceive.Zoomlevel < AlgoConfig.ZoomlevelClusterStop)
{
// Calculate data to be displayed
var clusterPoints = clusterAlgo.GetCluster(new ClusterInfo
{
ZoomLevel = jsonReceive.Zoomlevel,
});
var converted = DataConvert(clusterPoints);
// Prepare data to the client
reply = new JsonMarkersReply
{
Markers = converted,
Rid = sendid,
Polylines = clusterAlgo.Lines,
Msec = Sw(sw),
};
// Return client data
return reply;
}
// If we are here then there are no clustering
// The number of items returned is restricted to avoid json data overflow
IPoints filteredDataset = ClusterAlgorithmBase.FilterDataset(points, jsonReceive.Viewport);
IPoints filteredDatasetMaxPoints = new Points
{
Data = filteredDataset.Data
.Take(AlgoConfig.MaxMarkersReturned)
.ToList()
};
reply = new JsonMarkersReply
{
Markers = DataConvert(filteredDatasetMaxPoints),
Rid = sendid,
Polylines = clusterAlgo.Lines,
Mia = filteredDataset.Count - filteredDatasetMaxPoints.Count,
Msec = Sw(sw),
};
return reply;
}