The result dictionary contains ultimately all the points, therefore for each point there may be many entries in the dictionary that have a key close to the point. However, the Value associated to these points should be the same vertex.
The query cannot be expected to return a single result, so FirstOrDefault is the correct way to go, because all the elements selected should have the same Vertex, hence the first is a good as any.
The result dictionary contains ultimately all the points, therefore for each point there may be many entries in the dictionary that have a key close to the point. However, the Value associated to these points should be the same vertex.
The query cannot be expected to return a single result, so
FirstOrDefaultis the correct way to go, because all the elements selected should have the sameVertex, hence the first is a good as any.