public Boundary(Boundary b)
{
this.Minx = b.Minx;
this.Miny = b.Miny;
this.Maxx = b.Maxx;
this.Maxy = b.Maxy;
}
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);
}
static IPoints GenerateRandomDataset(int n, Boundary b)
{
b.Normalize();
// Random points
var list = new List<IP>();
for (var i = 0; i < n; i++)
{
var lat = (b.Miny + b.AbsY * Rand.NextDouble()).NormalizeLatitude();
var lon = (b.Minx + b.AbsX * Rand.NextDouble()).NormalizeLongitude();
list.Add(new P { I = Rand.Next(1000000000), C = 1, Y = lat, X = lon, T = i });
}
return new Points {Data = list};
}
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;
}
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 });
}
}
// To work properly it requires the p is already normalized
public static int[] GetPointMappedIds(IP p, Boundary grid, double deltax, double deltay)
{
var relativeX = p.X - grid.Minx;
var relativeY = p.Y - grid.Miny;
int idx, idy;
// Naive version, lon points near 180 and lat points near 90 are not clustered together
//idx = (int)(relativeX / deltax);
//idy = (int)(relativeY / deltay);
// end Naive version
/*
You have to draw a line with longitude values 180, -180 on papir to understand this
e.g. _deltaX = 20
longitude 150 170 180 -170 -150
| | | |
idx = 7 8 9 -9 -8
-10
here we want idx 8, 9, -10 and -9 be equal to each other, we set them to idx=8
then the longitudes from 170 to -170 will be clustered together
*/
var overlapMapMinX = (int)(LatLonInfo.MinLonValue / deltax) - 1;
var overlapMapMaxX = (int)(LatLonInfo.MaxLonValue / deltax);
// The deltaX = 20 example scenario, then set the value 9 to 8 and -10 to -9
// Similar to if (LatLonInfo.MaxLonValue % deltax == 0) without floating presicion issue
if (Math.Abs(LatLonInfo.MaxLonValue % deltax - 0) < Numbers.Epsilon)
{
overlapMapMaxX--;
overlapMapMinX++;
}
var idxx = (int)(p.X / deltax);
if (p.X < 0) idxx--;
if (Math.Abs(LatLonInfo.MaxLonValue % p.X - 0) < Numbers.Epsilon)
{
if (p.X < 0) idxx++;
else idxx--;
}
if (idxx == overlapMapMinX) idxx = overlapMapMaxX;
idx = idxx;
// Latitude never wraps around with Google Maps, ignore 90, -90 wrap-around for latitude
idy = (int)(relativeY / deltay);
return new[] { idx, idy };
}
public static bool IsInside(Boundary b, IP p)
{
return IsInside(b.Minx, b.Miny, b.Maxx, b.Maxy, p.X, p.Y, false, false);
}
// O(n), could be O(logn-ish) using range search or similar, no problem when points are <500.000
public static IPoints FilterDataset(IPoints dataset, Boundary viewport)
{
//return new Points { Data = dataset.Data.Where(i => MathTool.IsInsideWiden(viewport, i)).ToList() };
return new Points {Data = dataset.Data.Where(i => MathTool.IsInside(viewport, i)).ToList()};
}
public IPoints GetClusterResult(Boundary grid)
{
// Collect used buckets and return the result
var clusterPoints = new Points();
//O(m*n)
foreach (var item in BucketsLookup)
{
var bucket = item.Value;
if (!bucket.IsUsed) continue;
if (bucket.Points.Count < AlgoConfig.MinClusterSize) clusterPoints.Data.AddRange(bucket.Points.Data);
else
{
bucket.Centroid.C = bucket.Points.Count;
clusterPoints.Add(bucket.Centroid);
}
}
//var filtered = FilterDataset(clusterPoints, grid); // post filter data for client viewport
//return filtered; //not working properly when zoomed far out.
return clusterPoints; // return not post filtered
}
static void ReadSerializedFileAndCount()
{
var points = FileUtil.LoadDataSetFromFile();
var b = new Boundary { Minx = -179, Maxx = 179, Miny = -90, Maxy = 90 };
int i = points.Data.Count(p => MathTool.IsInside(b, p));
CWF("count: {0}", i);
}
static void PMapTest()
{
var b = new Boundary { Minx = -180, Maxx = 180, Miny = -90, Maxy = 90 };
const int dx = 20;
const int dy = 20;
var xy = GridCluster.GetPointMappedIds(new P { X = 175, Y = 35 }, b, dx, dy);
CWF("x: {0} y: {1}", xy[0], xy[1]);
xy = GridCluster.GetPointMappedIds(new P { X = 175, Y = 35 }, b, dx, dy);
CWF("x: {0} y: {1}", xy[0], xy[1]);
xy = GridCluster.GetPointMappedIds(new P { X = 180, Y = 35 }, b, dx, dy);
CWF("x: {0} y: {1}", xy[0], xy[1]);
xy = GridCluster.GetPointMappedIds((new P { X = 181, Y = 35 }).Normalize(), b, dx, dy);
CWF("x: {0} y: {1}", xy[0], xy[1]);
xy = GridCluster.GetPointMappedIds((new P { X = -181, Y = 35 }).Normalize(), b, dx, dy);
CWF("x: {0} y: {1}", xy[0], xy[1]);
}