I'm creating an application to create a circle of any radius given a central lat/lon coordinate. What I need to do is take the initial lat/lon coordinates and radius and calculate the points for the circle and add them to a dictionary list.

Here's what I have so far, but wit this, I get an error saying that 'An item with the same key has already been added' which leads me believe that it isn't actually converting the circle coordinates correctly.

```
private const double EARTH_RADIUS_NM = 3437.670013352;

private void plot(double lat, double lon, double radius)
{
    var coords = new Dictionary<double, double>();

    lat = ConvertToRadians(lat);
    lon = ConvertToRadians(lon);
    double d = radius / EARTH_RADIUS_NM;
    for(int x = 0; x <= 360; x++)
    {
        double brng = ConvertToRadians(x);
        var latRadians = Math.Asin(Math.Sin(lat) * Math.Cos(d) + Math.Cos(lat) * Math.Sin(d) * Math.Cos(brng));
        var lngRadians = lon + Math.Atan2(Math.Sin(brng) * Math.Sin(d) * Math.Cos(lat), Math.Cos(d) - Math.Sin(lat) * Math.Sin(latRadians));

        coords.Add(latRadians, lngRadians);
    }
}

public double ConvertToRadians(double angle)
{
    return (angle * Math.PI) / 180;
}

```

Example of use:

```
plot(33.9331486, -118.4320114, 0.5);

```

Can someone point me in the right direction?