public static PlaceOfInterest FindTheCenterPoint(PlaceOfInterest pt1, PlaceOfInterest pt2, PlaceOfInterest pt3)
{
double A1, A2, B1, B2, C1, C2, temp;
A1 = pt1.Longitude - pt2.Longitude;
B1 = pt1.Latitude - pt2.Latitude;
C1 = (Math.Pow(pt1.Longitude, 2) - Math.Pow(pt2.Longitude, 2) + Math.Pow(pt1.Latitude, 2) - Math.Pow(pt2.Latitude, 2)) / 2;
A2 = pt3.Longitude - pt2.Longitude;
B2 = pt3.Latitude - pt2.Latitude;
C2 = (Math.Pow(pt3.Longitude, 2) - Math.Pow(pt2.Longitude, 2) + Math.Pow(pt3.Latitude, 2) - Math.Pow(pt2.Latitude, 2)) / 2;
temp = A1 * B2 - A2 * B1;
PlaceOfInterest PC;
if (temp == 0)
{
PC = new PlaceOfInterest(0, pt1.Latitude, pt1.Longitude, "circle centre");
}
else
{
PC = new PlaceOfInterest(0, (A1 * C2 - A2 * C1) / temp, (C1 * B2 - C2 * B1) / temp, "circle centre");
}
return(PC);
}
public static List <PlaceOfInterest> GrahmConvexHull(List <PlaceOfInterest> pointList)
{
List <PlaceOfInterest> hull = new List <PlaceOfInterest>();
List <PlaceOfInterest> noDuplicates = RemoveDuplicate(pointList);
noDuplicates.Sort();
PlaceOfInterest pivot = noDuplicates[0];
noDuplicates.RemoveAt(0);
noDuplicates.Sort(new SortRadial(pivot));
hull.Add(pivot);
hull.Add(noDuplicates[0]); noDuplicates.RemoveAt(0);
hull.Add(noDuplicates[0]); noDuplicates.RemoveAt(0);
while (noDuplicates.Count > 0)
{
hull.Add(noDuplicates[0]); noDuplicates.RemoveAt(0);
while (!Validate(hull))
{
hull.RemoveAt(hull.Count - 2);
}
}
hull.Add(pivot);
return(hull);
}
public static List <PlaceOfInterest> MonoStoneConvexHull(List <PlaceOfInterest> points)
{
points.Sort();
if (points.Count <= 3)
{
return(new List <PlaceOfInterest>(points));
}
List <PlaceOfInterest> upperHull = new List <PlaceOfInterest>();
foreach (PlaceOfInterest point in points)
{
PlaceOfInterest p2 = point;
while (upperHull.Count >= 2)
{
PlaceOfInterest pivot = upperHull[upperHull.Count - 2];
PlaceOfInterest p1 = upperHull[upperHull.Count - 1];
if (Calculation.SignedArea(pivot, p1, p2) <= 0)
{
upperHull.RemoveAt(upperHull.Count - 1);
}
else
{
break;
}
}
upperHull.Add(p2);
}
upperHull.RemoveAt(upperHull.Count - 1);
List <PlaceOfInterest> lowerHull = new List <PlaceOfInterest>();
for (int i = points.Count - 1; i >= 0; i--)
{
PlaceOfInterest p2 = points[i];
while (lowerHull.Count >= 2)
{
PlaceOfInterest pivot = lowerHull[lowerHull.Count - 2];
PlaceOfInterest p1 = lowerHull[lowerHull.Count - 1];
if (Calculation.SignedArea(pivot, p1, p2) <= 0)
{
lowerHull.RemoveAt(lowerHull.Count - 1);
}
else
{
break;
}
}
lowerHull.Add(p2);
}
lowerHull.RemoveAt(lowerHull.Count - 1);
if (!(Enumerable.SequenceEqual(upperHull, lowerHull)))
{
upperHull.AddRange(lowerHull);
}
return(upperHull);
}
public static double CalculateAngle(PlaceOfInterest a, PlaceOfInterest b, PlaceOfInterest c)
{
double bc = PythagorasDistance(b, c);
double ac = PythagorasDistance(a, c);
double ab = PythagorasDistance(b, a);
return(Math.Acos((Math.Pow(bc, 2) - Math.Pow(ac, 2) + Math.Pow(ab, 2)) / (2 * bc * ab)) * 180 / Math.PI);
//double a = Math.Pow(p2.Latitude - p1.Latitude, 2) + Math.Pow(p2.Longitude - p1.Longitude, 2);
//double b = Math.Pow(p2.Latitude - p3.Latitude, 2) + Math.Pow(p2.Longitude - p3.Longitude, 2);
//double c = Math.Pow(p3.Latitude - p1.Latitude, 2) + Math.Pow(p3.Longitude - p1.Longitude, 2);
//return Math.Acos((a + b - c) / Math.Sqrt(4 * a * b));
}
private bool CheckDuplicacy(PlaceOfInterest poi, HashSet <PlaceOfInterest> initialHashset)
{
bool duplicate = false;
foreach (PlaceOfInterest p in initialHashset)
{
if (p.Equals(poi))
{
duplicate = true;
}
}
return(duplicate);
}
private static void FindSmallestAngle(PlaceOfInterest p1, PlaceOfInterest p2, List<PlaceOfInterest> hullPoints)
{
PlaceOfInterest k = null;
foreach (PlaceOfInterest p in hullPoints)
{
if (p != p1 && p != p2)
{
k = p;
break;
}
}
double angle = Calculation.CalculateAngle(p1, k, p2);
foreach (PlaceOfInterest h in hullPoints)
{
if (!h.Equals(p1) && !h.Equals(p2) && !h.Equals(k) && angle > Calculation.CalculateAngle(p1, h, p2))
{
k = h;
angle = Calculation.CalculateAngle(p1, k, p2);
}
}
if (angle >= 90)
{
centerPoint = new PlaceOfInterest(1, (p1.Latitude + p2.Latitude )/ 2, (p1.Longitude + p2.Longitude) / 2, "");
radius = Calculation.PythagorasDistance(centerPoint, p1);
pointOne = p1; pointTwo = k; pointThree = p2;
}
else if (angle < 90 && Calculation.CalculateAngle(p1, p2, k) < 90 && Calculation.CalculateAngle(p2, p1, k) < 90)
{
//define the circle
centerPoint = Calculation.FindTheCenterPoint(p1, k, p2);
radius = Calculation.PythagorasDistance(centerPoint, p2);
pointOne = p1; pointTwo = k; pointThree = p2;
}
else if (Calculation.CalculateAngle(p1, p2, k) > 90)
{
FindSmallestAngle(p1, k, hullPoints);
}
else if (Calculation.CalculateAngle(p2, p1, k) > 90)
{
FindSmallestAngle(p2, k, hullPoints);
}
}
public static List <PlaceOfInterest> RemoveDuplicate(List <PlaceOfInterest> pointList)
{
List <PlaceOfInterest> noDuplicate = new List <PlaceOfInterest>();
PlaceOfInterest compareValue = new PlaceOfInterest(0, 0, 0, "");
foreach (PlaceOfInterest poi in pointList.ToList())
{
if (!poi.Equals(compareValue))
{
noDuplicate.Add(poi);
compareValue = poi;
}
}
return(noDuplicate);
}
private List <PlaceOfInterest> GetLocationTestDat()
{
PlaceOfInterest p1 = new PlaceOfInterest(1, 1, 1, "");
PlaceOfInterest p2 = new PlaceOfInterest(1, 1, -1, "");
PlaceOfInterest p3 = new PlaceOfInterest(1, -1, 1, "");
PlaceOfInterest p4 = new PlaceOfInterest(1, -1, -1, "");
PlaceOfInterest p5 = new PlaceOfInterest(1, 0, 0, "");
PlaceOfInterest p6 = new PlaceOfInterest(1, 2, 2, "");
List <PlaceOfInterest> list = new List <PlaceOfInterest>();
locationList.Add(p1);
locationList.Add(p2);
locationList.Add(p3);
locationList.Add(p4);
locationList.Add(p5);
locationList.Add(p6);
return(locationList);
}
private List <PlaceOfInterest> GetLocationData()
{
string url = @"http://developer.kensnz.com/getlocdata";
using (WebClient client = new WebClient())
{
var json = client.DownloadString(url);
JavaScriptSerializer ser = new JavaScriptSerializer();
var jsonArray = ser.Deserialize <Dictionary <string, string>[]>(json);
richTextBox1.AppendText(json);
foreach (Dictionary <string, string> map in jsonArray)
{
int userid = int.Parse(map["userid"]);
int id = int.Parse(map["id"]);
double latittude = double.Parse(map["latitude"]);
double longitude = double.Parse(map["longitude"]);
string description = map["description"];
if (latittude > -47 && latittude < -45 && longitude > 164 && longitude < 170)
{
PlaceOfInterest poi = new PlaceOfInterest(userid, latittude, longitude, description);
if (CheckDuplicacy(poi, initialHashset))
{
break;
}
else
{
initialHashset.Add(poi);
}
}
}
}
locationList = initialHashset.ToList();
return(locationList);
}
public static double PythagorasDistance(PlaceOfInterest p1, PlaceOfInterest p2)
{
return(Math.Sqrt(Math.Pow(p2.Latitude - p1.Latitude, 2) + Math.Pow(p2.Longitude - p1.Longitude, 2)));
}
public static double SignedArea(PlaceOfInterest a, PlaceOfInterest b, PlaceOfInterest c)
{
return((a.Latitude * b.Longitude) - (b.Latitude * a.Longitude) + (b.Latitude * c.Longitude) - (c.Latitude * b.Longitude) + (c.Latitude * a.Longitude) - (a.Latitude * c.Longitude));
}
