Ionic 3+ distance between two position points

    
    getDistance()
    {
      console.log('Get Distance');
      
      var distanceInMeters = google.maps.geometry.spherical.computeDistanceBetween(
        new google.maps.LatLng({
          lat: Number(this.coachData.geolocation_lat), 
          lng: Number(this.coachData.geolocation_long), 
        }),
        new google.maps.LatLng({
          lat: Number(this.latitude),
          lng: Number(this.longitude),
        })
        );
        
        // Outputs: Distance in Meters:
        console.log("Distance in Meters: ", distanceInMeters);
        
        // Outputs: Distance in Kilometers: 
        console.log("Distance in Kilometers: ", (distanceInMeters * 0.001));

        // Outputs: Distance in miles: 

        console.log("Distance in Miles: ", (distanceInMeters * 0.000621371));
        
      }
      

To Prevent Spherical error just modify your index.html file

  <script src="https://maps.google.com/maps/api/js?key=AIzaSyC-XXXXXXXXXXXXXXXX&libraries=geometry"></script>

And declare

declare var google;