public static GeoCoord Minimizer(Func<GeoCoord, double> f, GeoCoord guess)
{
var ret = Minimizer((x) => f(new GeoCoord(x[0], x[1])), new double[] { guess.Latitude, guess.Longitude }, new double[] { 0.1, 0.1 });
return new GeoCoord(ret[0], ret[1]);
}
public Point OffsetInMeters(GeoCoord geoC)
{
// Determine the actual size of the geography.
// From http://en.wikipedia.org/wiki/Latitude,
// and assuming the earth is spherical (e=1)
double x = -(this.Longitude - geoC.Longitude) * LonDegreeSizeInMeters;
double y = (this.Latitude - geoC.Latitude) * LatDegreeSizeInMeters;
var ret = new Point(x, y);
return ret;
}
public GeoCoord FromOffset(double x, double y)
{
double Longitude = this.Longitude + x / LonDegreeSizeInMeters;
double Latitude = this.Latitude - y / LatDegreeSizeInMeters;
var ret = new GeoCoord(Latitude, Longitude);
return ret;
}
/// <returns>Meters squared</returns>
public double DistSqr(GeoCoord x0)
{
var offsetMeters = OffsetInMeters(x0);
return offsetMeters.Square();
}
internal double Strength(GeoCoord x)
{
var ret = FitFunction(x, new GeoCoord(this.CenterLatitude, this.CenterLongitude), 1 / Spread);
return ret;
}
internal static double FitFunction(GeoCoord x, GeoCoord x0, double invWidth)
{
var ret = 100 * Math.Exp(-x.DistSqr(x0) * invWidth * invWidth);
return ret;
}