How to do spatial polygon search with Lucene.net + Spatial4n? - asp.net

Question

I have a list of companies, each with a lat lng. In addition, each company has a radius within which they are prepared to work. What I need to do is be able to perform a search around a given location + radius and see if that radius overlaps with the working radius of any companies.
I'm using Lucene.net 2.9.4 (Umbraco) and am looking to use Spatial4n with it. I've currently got the Spatial4n 0.3 lib, and have compiled the lucene.net.contrib.spacial project against it (after having to mash together a bunch of code from the latest lucene repo ad some things seem to be missing).
So my question is, how would I a) go about indexing a company and their work radius? and b) search for companies who are prepared to work within a given search radius?

Answer 1

Can't answer a) but for b), get the distance between the 2 coordinates, and if it's less than the sum of both radii, then it's a match (i.e. overlap).
Get Distance:
public static double GetDistance(double latitude1, double longitude1, double latitude2, double longitude2, DistanceUnits distanceUnits = DistanceUnits.Miles)
{
try
{
// Earth radius in kilometers via NASA as of 2016 - https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html
const double earthRadiusKilometers = 6378.137;
var latRadians = (latitude2 - latitude1).ToRadians();
var lonRadians = (longitude2 - longitude1).ToRadians();
var a = Math.Sin(latRadians / 2) *
Math.Sin(latRadians / 2) +
Math.Cos(latitude1.ToRadians()) *
Math.Cos(latitude2.ToRadians()) *
Math.Sin(lonRadians / 2) *
Math.Sin(lonRadians / 2);
var radianDistance = 2 * Math.Asin(Math.Min(1, Math.Sqrt(a)));
switch (distanceUnits)
{
case DistanceUnits.Kilometers:
{
return radianDistance * earthRadiusKilometers;
}
case DistanceUnits.Miles:
{
return radianDistance * ConvertKilometersToMiles(earthRadiusKilometers);
}
}
return radianDistance;
}
catch
{
return double.MaxValue;
}
}
public static double ConvertKilometersToMiles(double kilometers)
{
return kilometers * 0.621371192;
}
public enum DistanceUnits
{
Miles,
Kilometers,
Radians
}