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Revision as of 16:21, 11 July 2012 by jasfox (Talk | contribs)

HERE Maps API - How to find the nearest Marker

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This code example shows how to find the nearest Marker from any point on the map. The code is useful for finding the Markers that are located close to the user's current position or destination.

Article Metadata
Code ExampleTested with
Devices(s): Firefox , Internet Explorer, Google Chrome, Opera
Compatibility
Platform(s): Web Browser
Dependencies: Nokia Maps API 2.2.1
Article
Keywords: Nokia Maps, JavaScript, Marker
Created: Maveric (13 Nov 2011)
Last edited: jasfox (11 Jul 2012)

Introduction

This example demonstrates how to find the nearest map Marker from any point on the map. In the example there are five Markers on the Nokia Map and you can click anywhere on the map. Based on where you clicked, the script will calculate the distance to the Marker that is located closest to the point of your click. To display the result, the label text of the Marker is retrieved and shown on the page.

NearestMarkerExample..png

Example code

After setting up five markers, the code continues by adding a click event to the map.

var eventTarget = nokia.maps.dom.EventTarget;        
var eventCheck = document.getElementById("map");
eventTarget(eventCheck);
eventCheck.addListener("click", function(evt)
{ var coords = map.pixelToGeo(evt.targetX , evt.targetY);
findNearestMarker (coords);
}, false);

The findNearestMarker() method iterates through each marker on the map and calculates the distance. The lowest distance so far is kept.

function findNearestMarker(coords) { 
var minDist = 1000;
var nearest_text = "*None*";
for (i=0; i< map.objects.getLength(); i++)
{
if ( map.objects.get(i) instanceof nokia.maps.map.StandardMarker ) {
var markerDist = map.objects.get(i).coordinate.distance(coords);
if (markerDist < minDist) {
minDist = markerDist;
nearest_text = map.objects.get(i).text
}
}
}
 
alert (nearest_text);
}

The fully coded example can be found here : NearestMarkerExample.zip

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