public static double DistanceTo(this Coordinates baseCoordinates, Coordinates targetCoordinates, UnitOfLength unitOfLength)
{
var baseRad = Math.PI * baseCoordinates.Latitude / 180;
var targetRad = Math.PI * targetCoordinates.Latitude / 180;
var theta = baseCoordinates.Longitude - targetCoordinates.Longitude;
var thetaRad = Math.PI * theta / 180;
double dist =
Math.Sin(baseRad) * Math.Sin(targetRad) + Math.Cos(baseRad) *
Math.Cos(targetRad) * Math.Cos(thetaRad);
dist = Math.Acos(dist);
dist = dist * 180 / Math.PI;
dist = dist * 60 * 1.1515;
return(unitOfLength.ConvertFromMiles(dist));
}
public SortedDictionary <double, Entry> FilterByLocation(Coordinates center, double distance = 5, UnitOfLength length = null)
{
if (length == null)
{
length = UnitOfLength.Kilometers;
}
SortedDictionary <double, Entry> result = new SortedDictionary <double, Entry>();
foreach (var entry in RepeaterBookData.Entries)
{
var d = entry.Coordinates.DistanceTo(center, length);
if (d <= distance)
{
while (result.ContainsKey(d))
{
//add an arbitrarily tiny amount, just to keep our keys unique
d = d + 0.0000000001;
}
result.Add(d, entry);
}
}
return(result);
}