Geo Fencing - point inside/outside polygon

Question

I would like to determine a polygon and implement an algorithm which would check if a point is inside or outside the polygon.

Does anyone know if there is any exampl

Answer 1

The complete solution in asp.Net C#, you can see the complete detail here, you can see how to find point(lat,lon) whether its inside or Outside the Polygon using the latitude and longitudes ? Article Reference Link

private static bool checkPointExistsInGeofencePolygon(string latlnglist, string lat, string lng) {

    List objList = new List();
    // sample string should be like this strlatlng = "39.11495,-76.873259|39.114588,-76.872808|39.112921,-76.870373|";
    string[] arr = latlnglist.Split('|');
    for (int i = 0; i <= arr.Length - 1; i++)
    {
        string latlng = arr[i];
        string[] arrlatlng = latlng.Split(',');

        Loc er = new Loc(Convert.ToDouble(arrlatlng[0]), Convert.ToDouble(arrlatlng[1]));
        objList.Add(er);
    }
    Loc pt = new Loc(Convert.ToDouble(lat), Convert.ToDouble(lng));

    if (IsPointInPolygon(objList, pt) == true)
    {
          return true;
    }
    else
    {
           return false;
    }
}
private static bool IsPointInPolygon(List poly, Loc point)
{
    int i, j;
    bool c = false;
    for (i = 0, j = poly.Count - 1; i < poly.Count; j = i++)
    {
        if ((((poly[i].Lt <= point.Lt) && (point.Lt < poly[j].Lt)) |
            ((poly[j].Lt <= point.Lt) && (point.Lt < poly[i].Lt))) &&
            (point.Lg < (poly[j].Lg - poly[i].Lg) * (point.Lt - poly[i].Lt) / (poly[j].Lt - poly[i].Lt) + poly[i].Lg))
            c = !c;
    }
    return c;
}