Building a Geo Targeting in Swift

Im trying to implement geo targeting functionality with CLRegion. But When I run this app the MKCircle didn't show up, can anyone tell me which part is wrong?

 func setupData(){
    if CLLocationManager.isMonitoringAvailableForClass(CLCircularRegion.self){

    let tripspotRegion = [
        tripSpot( title: "一中商圈", coordinate: CLLocationCoordinate2DMake(24.149062, 120.684891), regionRadius: 300.0, location: "台中一中", type: "food"),
        tripSpot( title: "逢甲夜市", coordinate: CLLocationCoordinate2DMake(24.180407, 120.645086), regionRadius: 300.0, location:"台中逢甲", type: "food"),
        tripSpot( title: "東海商圈", coordinate: CLLocationCoordinate2DMake(24.181143, 120.593158), regionRadius: 300.0, location: "東海商圈", type: "food")]
    //set annotation
    let coordinate = CLLocationCoordinate2D()
    let regionRadius = 300.0
    let title = "title"
    let region = CLCircularRegion(center: CLLocationCoordinate2D(latitude: coordinate.latitude,longitude: coordinate.longitude), radius: regionRadius, identifier: title)
    //set annotation
    let tripSpotAnnotation = MKPointAnnotation()

    tripSpotAnnotation.coordinate = coordinate
    tripSpotAnnotation.title = "\(title)"
    mapView.addAnnotations(tripspotRegion)
   locationManager.startMonitoringForRegion(region)
    // draw a circle
        let circle = MKCircle(centerCoordinate: coordinate, radius: regionRadius)

        mapView.addOverlay(circle)
    }
    // check if can monitor region
        else{

            print("system can't track regions")



           }
}

You have put three coordinates in an array, but then you aren't doing anything with them. You are creating a new coordinate but not initialising it, so your region and overlay will be at (0,0). I think you meant to use the tripspotArray to add the regions/overlays:

func setupData(){
    if CLLocationManager.isMonitoringAvailableForClass(CLCircularRegion.self) {

        let tripspotRegion = [
            tripSpot( title: "一中商圈", coordinate: CLLocationCoordinate2DMake(24.149062, 120.684891), regionRadius: 300.0, location: "台中一中", type: "food"),
            tripSpot( title: "逢甲夜市", coordinate: CLLocationCoordinate2DMake(24.180407, 120.645086), regionRadius: 300.0, location:"台中逢甲", type: "food"),
            tripSpot( title: "東海商圈", coordinate: CLLocationCoordinate2DMake(24.181143, 120.593158), regionRadius: 300.0, location: "東海商圈", type: "food")]

        for aSpot in tripspotRegion {
            //set annotation
            let coordinate =aSpot.coordindate
            let regionRadius = aSpot.regionRadius
            let title = aSpot.title
            let region = CLCircularRegion(center: coordinate, radius: regionRadius, identifier: title)
//set annotation
            let tripSpotAnnotation = MKPointAnnotation()

            tripSpotAnnotation.coordinate = coordinate
            tripSpotAnnotation.title = title
            mapView.addAnnotations([tripSpotAnnotation])
            locationManager.startMonitoringForRegion(region)
// draw a circle
            let circle = MKCircle(centerCoordinate: coordinate, radius: regionRadius)
            mapView.addOverlay(circle)
        }
    } else{
        print("system can't track regions")
    }
}