public void Test_S2LatLng_TestBasic()
{
S2LatLng ll_rad = S2LatLng.FromRadians(S2.M_PI_4, S2.M_PI_2);
Assert.Equal(S2.M_PI_4, ll_rad.LatRadians);
Assert.Equal(S2.M_PI_2, ll_rad.LngRadians);
Assert.True(ll_rad.IsValid());
S2LatLng ll_deg = S2LatLng.FromDegrees(45, 90);
Assert.Equal(ll_rad, ll_deg);
Assert.True(ll_deg.IsValid());
Assert.False(S2LatLng.FromDegrees(-91, 0).IsValid());
Assert.False(S2LatLng.FromDegrees(0, 181).IsValid());
S2LatLng bad = S2LatLng.FromDegrees(120, 200);
Assert.False(bad.IsValid());
S2LatLng better = bad.Normalized();
Assert.True(better.IsValid());
Assert.Equal(S1Angle.FromDegrees(90), better.Lat());
Assert2.DoubleEqual(S1Angle.FromDegrees(-160).Radians, better.LngRadians);
bad = S2LatLng.FromDegrees(-100, -360);
Assert.False(bad.IsValid());
better = bad.Normalized();
Assert.True(better.IsValid());
Assert.Equal(S1Angle.FromDegrees(-90), better.Lat());
Assert2.DoubleEqual(0.0, better.LngRadians);
Assert.True((S2LatLng.FromDegrees(10, 20) + S2LatLng.FromDegrees(20, 30)).
ApproxEquals(S2LatLng.FromDegrees(30, 50)));
Assert.True((S2LatLng.FromDegrees(10, 20) - S2LatLng.FromDegrees(20, 30)).
ApproxEquals(S2LatLng.FromDegrees(-10, -10)));
Assert.True((0.5 * S2LatLng.FromDegrees(10, 20)).
ApproxEquals(S2LatLng.FromDegrees(5, 10)));
// Check that Invalid() returns an invalid point.
S2LatLng invalid = S2LatLng.Invalid;
Assert.False(invalid.IsValid());
// Check that the default constructor sets latitude and longitude to 0.
S2LatLng default_ll = S2LatLng.Center;
Assert.True(default_ll.IsValid());
Assert.Equal(0, default_ll.LatRadians);
Assert.Equal(0, default_ll.LngRadians);
}
// Returns the minimum distance from X to the latitude line segment defined by
// the given latitude and longitude interval.
private static S1Angle GetDistance(S2LatLng x, S1Angle lat, S1Interval interval)
{
Assert.True(x.IsValid());
Assert.True(interval.IsValid());
// Is X inside the longitude interval?
if (interval.Contains(x.LngRadians))
{
return(S1Angle.FromRadians((x.Lat() - lat).Abs()));
}
// Return the distance to the closer endpoint.
return(new[] { x.GetDistance(new S2LatLng(lat, S1Angle.FromRadians(interval.Lo))),
x.GetDistance(new S2LatLng(lat, S1Angle.FromRadians(interval.Hi))) }.Min());
}
