Question

1

Check if a latitude and longitude is within a circle google maps

rated 0 times [ 6] [ 5] / answers: 1 / hits: 28093 / 10 Years ago, thu, july 10, 2014, 12:00:00

Below is the desired result, which I'm looking for

enter

What I would like to know is:

I have created the circle using center point lat lang and radius around it. Now I want to know, how to check (calculate) if a latitude and longitude is either inside or outside the area I would appreciate if you can give me code example in Javascript. I'm using Google Maps API V3.

I found this function but not working as expected for me:

function arePointsNear(checkPoint, centerPoint) {

    var sw = new google.maps.LatLng(centerPoint.lat() - 0.005, centerPoint.lng() - 0.005);

    var ne = new google.maps.LatLng(centerPoint.lat() + 0.005, centerPoint.lng() + 0.005);

    var bounds = new google.maps.LatLngBounds(sw, ne);

    if (bounds.contains (checkPoint)){

        return true;

    }

    return false;

}

Any help will be great.. thanks in advance!!

Answers

Only authorized users can answer the question. Please sign in first, or register a free account.

antonb

Add To Favorites

Follow

Total Points: 424

Total Questions: 104

Total Answers: 101

Location: Serbia

Member since Tue, Jul 26, 2022

2 Years ago

answered 10 Years ago neildrews · Accepted Answer

For such short distances, and when the accuracy doesn't have to be exact to the centimeter, you can treat the surface of the earth as flat. Calculate a conversion from degrees to kilometers at the latitude of the center point, then the Pythagorean theorem can be used to get the distance:

function arePointsNear(checkPoint, centerPoint, km) {

  var ky = 40000 / 360;

  var kx = Math.cos(Math.PI * centerPoint.lat / 180.0) * ky;

  var dx = Math.abs(centerPoint.lng - checkPoint.lng) * kx;

  var dy = Math.abs(centerPoint.lat - checkPoint.lat) * ky;

  return Math.sqrt(dx * dx + dy * dy) <= km;

}

Demo: http://jsfiddle.net/Guffa/57gQa/

Note: The code doesn't take into consideration if you are passing the 0/360 longitude. If that is the case, you would have to normalize the longitudes first.