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

C# code

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;
}

Location class

public class Loc
{
    private double lt;
    private double lg;

    public double Lg
    {
        get { return lg; }
        set { lg = value; }
    }

    public double Lt
    {
        get { return lt; }
        set { lt = value; }
    }

    public Loc(double lt, double lg)
    {
        this.lt = lt;
        this.lg = lg;
    }
}