Vince Lowe Vince Lowe - 5 months ago 62
Javascript Question

Google maps drag rectangle to select markers

I am trying to draw a rectangle on the google map and detect if any markers are within the bounds of the rectangle.

To draw a rectangle you hold shift key, click and drag.

I have a working sample here - http://jsfiddle.net/dbwPQ/3/

Why does the .contains method only return true if the rectangle is drawn from bottom left to top right or top right to bottom left.

And yet the same area drawn from top left to bottom right or bottom right to top left returns false????

if (boundsSelectionArea.contains(markers[key].position))
//if (gribBoundingBox.getBounds().getNorthEast().lat() <= markers[key].position.lat() &&
// gribBoundingBox.getBounds().getSouthWest().lat() >= markers[key].position.lat() &&
// gribBoundingBox.getBounds().getSouthWest().lng() <= markers[key].position.lng() &&
// gribBoundingBox.getBounds().getNorthEast().lng() >= markers[key].position.lng() )
{
//if(flashMovie !== null && flashMovie !== undefined) {
console.log("User selected:" + key + ", id:" + markers[key].id);
//}
} else {
//if(flashMovie !== null && flashMovie !== undefined) {
console.log("User NOT selected:" + key + ", id:" + markers[key].id);
//}
}


UPDATE this works but i dont know why? http://jsfiddle.net/dbwPQ/4/

Answer

It looks like the google.maps.Rectangle.getBounds is returning "invalid" bounds

key:Vince posn:(53.801279, -1.5485670000000482) out of bnds:((55.45394132943307, -4.0869140625), (52.72298552457069, 1.7138671875))
key:Vince posn:(53.801279, -1.5485670000000482) in bnds:((52.26815737376817, -4.04296875), (55.65279803318956, 2.2412109375))

If you extend an empty google.maps.LatLng object with your two corners, it will work:

google.maps.event.addListener(themap, 'mousemove', function (e) {
    if (mouseIsDown && shiftPressed) {
        if (gribBoundingBox !== null) // box exists
        {
            bounds.extend(e.latLng);                
            gribBoundingBox.setBounds(bounds); // If this statement is enabled, I lose mouseUp events

        } else // create bounding box
        {
            bounds = new google.maps.LatLngBounds();
            bounds.extend(e.latLng);
            gribBoundingBox = new google.maps.Rectangle({
                map: themap,
                bounds: bounds,
                fillOpacity: 0.15,
                strokeWeight: 0.9,
                clickable: false
            });
        }
    }
});

working example

code snippet:

var map;
var markers = {};
var bounds = null;
// add marker to object
var posi = new google.maps.LatLng(53.801279, -1.548567);
var name = 'Vince';
markers[name] = {};
markers[name].id = 1;
markers[name].lat = 53.801279;
markers[name].lng = -1.548567;
markers[name].state = 'Online';
markers[name].position = posi;
markers[name].selected = false;

$(document).ready(function() {

  var mapOptions = {
    zoom: 5,
    center: new google.maps.LatLng(53.801279, -1.548567),
    mapTypeId: google.maps.MapTypeId.ROADMAP
  };
  map = new google.maps.Map(document.getElementById('map'), mapOptions);
  var infowindow = new google.maps.InfoWindow();
  for (var key in markers) {
    var marker = new google.maps.Marker({
      position: new google.maps.LatLng(markers[key].lat, markers[key].lng),
      map: map
    });
    markers[key].marker = marker;

    google.maps.event.addListener(marker, 'click', (function(marker, key) {
      return function() {
        infowindow.setContent(key);
        infowindow.open(map, marker);
      }
    })(marker, key));
  }

  // Start drag rectangle to select markers !!!!!!!!!!!!!!!!
  var shiftPressed = false;

  $(window).keydown(function(evt) {
    if (evt.which === 16) { // shift
      shiftPressed = true;
    }
  }).keyup(function(evt) {
    if (evt.which === 16) { // shift
      shiftPressed = false;
    }
  });

  var mouseDownPos, gribBoundingBox = null,
    mouseIsDown = 0;
  var themap = map;

  google.maps.event.addListener(themap, 'mousemove', function(e) {
    if (mouseIsDown && shiftPressed) {
      if (gribBoundingBox !== null) // box exists
      {
        bounds.extend(e.latLng);
        gribBoundingBox.setBounds(bounds); // If this statement is enabled, I lose mouseUp events

      } else // create bounding box
      {
        bounds = new google.maps.LatLngBounds();
        bounds.extend(e.latLng);
        gribBoundingBox = new google.maps.Rectangle({
          map: themap,
          bounds: bounds,
          fillOpacity: 0.15,
          strokeWeight: 0.9,
          clickable: false
        });
      }
    }
  });

  google.maps.event.addListener(themap, 'mousedown', function(e) {
    if (shiftPressed) {

      mouseIsDown = 1;
      mouseDownPos = e.latLng;
      themap.setOptions({
        draggable: false
      });
    }
  });

  google.maps.event.addListener(themap, 'mouseup', function(e) {
    if (mouseIsDown && shiftPressed) {
      mouseIsDown = 0;
      if (gribBoundingBox !== null) // box exists
      {
        var boundsSelectionArea = new google.maps.LatLngBounds(gribBoundingBox.getBounds().getSouthWest(), gribBoundingBox.getBounds().getNorthEast());

        for (var key in markers) { // looping through my Markers Collection	

          //                    if (boundsSelectionArea.contains(markers[key].marker.getPosition())) 
          if (gribBoundingBox.getBounds().contains(markers[key].marker.getPosition())) {
            //if(flashMovie !== null && flashMovie !== undefined) {
            markers[key].marker.setIcon("http://maps.google.com/mapfiles/ms/icons/blue.png")
            document.getElementById('info').innerHTML += "key:" + key + " posn:" + markers[key].marker.getPosition() + " in bnds:" + gribBoundingBox.getBounds() + "<br>";
            // console.log("User selected:" + key + ", id:" + markers[key].id);
            //}   
          } else {
            //if(flashMovie !== null && flashMovie !== undefined) {
            markers[key].marker.setIcon("http://maps.google.com/mapfiles/ms/icons/red.png")
            document.getElementById('info').innerHTML += "key:" + key + " posn:" + markers[key].marker.getPosition() + " out of bnds:" + gribBoundingBox.getBounds() + "<br>";
            // console.log("User NOT selected:" + key + ", id:" + markers[key].id);
            //} 
          }
        }

        gribBoundingBox.setMap(null); // remove the rectangle
      }
      gribBoundingBox = null;

    }

    themap.setOptions({
      draggable: true
    });
    //stopDraw(e);
  });

});
#map {
  height: 500px;
  width: 500px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js"></script>
<div id="map"></div>
<div id="info"></div>