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raintrooper
Asked: 2020-10-31 08:30:02 +0800 CST 2020-10-31 08:30:02 +0800 CST

Show marker in Google Maps Api Js (Only if it is inside the radius circle)

  • 772

I need to show markers on a map, only if they are within the radius of the circle shown on the screen. But I don't know how to validate whether or not the marker is within the radius.

var myLatLng = { lat: 14.151171, lng: -90.841083 };
var myLatLng2 = { lat: 14.15009000, lng: -90.84334708 };

function initMap() {

    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 4,
      center: myLatLng,
      mapTypeId: 'terrain',
      zoom: 18
    });
  
    var markerYesShow = new google.maps.Marker({
      position: myLatLng,
      map: map,
      title: 'Yes Show Into Radio'
    });
    
    var markerNotShow = new google.maps.Marker({
      position: myLatLng2,
      map: map,
      title: 'Not Show '
    });
  
    var alerta = new google.maps.Circle({
      strokeColor: '#FF0000',
      strokeOpacity: 0.8,
      strokeWeight: 2,
      fillColor: '#FF0000',
      fillOpacity: 0.35,
      map: map,
      center: myLatLng,
      radius: 100
    });
}
/* Always set the map height explicitly to define the size of the div
 * element that contains the map. */
#map {
  height: 100%;
}
/* Optional: Makes the sample page fill the window. */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}
<div id="map"></div>
 <!-- Replace the value of the key parameter with your own API key. -->
<script async defer
src="https://maps.googleapis.com/maps/api/js??key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initMap">
</script>

javascript

1 Answers

  1. Best Answer

    You have a circle with center at coordinates X1,Y1 and radius R. What you need is to check that the point (X,Y) is at a distance from (X1,Y1) less than the value of R:

    let ejeX=10,ejeY=10;
let radio=5;

function dentroDelCirculo(x,y) {
 return ((ejeX-x)**2 + (ejeY-y)**2) <= radio**2;
}

console.log('dentro?:' + dentroDelCirculo(14,10));
console.log('dentro?:' + dentroDelCirculo(75,35));

    Note: **this is the power notation in JS, but in an older browser it might not work, so you can multiply each value by itself or use Math.powto do the operation.

    • 2