×
Namespaces

Variants
Actions
(Difference between revisions)

HERE Maps API - Converting a map screen pixel to a geo coordinate

From Nokia Developer Wiki
Jump to: navigation, search
jasfox (Talk | contribs)
m (Jasfox - - Example code)
jasfox (Talk | contribs)
m (Jasfox - link)
 
(9 intermediate revisions by 2 users not shown)
Line 1: Line 1:
[[Category:Nokia Maps]][[Category:Code Snippet]][[Category:JavaScript]]
+
[[Category:HERE Maps]][[Category:JavaScript]][[Category:Code Examples]]
 
{{Abstract|This article explains how to convert a map screen's pixel to a geocoordinate. This is useful when we want to know the geocoordinates of the point user had clicked. }}
 
{{Abstract|This article explains how to convert a map screen's pixel to a geocoordinate. This is useful when we want to know the geocoordinates of the point user had clicked. }}
  
{{ArticleMetaData
+
{{ArticleMetaData <!-- v1.2 -->
|sourcecode= <!-- Link to example source code e.g. [[Media:The Code Example ZIP.zip]] -->
+
|sourcecode=  [https://github.com/heremaps/examples/blob/master/maps_api_for_javascript/simple-examples/pixel-to-geocoordinate.html pixel-to-geocoordinate.html]
 
|installfile= <!-- Link to installation file (e.g. [[Media:The Installation File.sis]]) -->
 
|installfile= <!-- Link to installation file (e.g. [[Media:The Installation File.sis]]) -->
|devices=Google Chrome, Mozilla Firefox, Internet Explorer, Opera
+
|devices= Google Chrome, Mozilla Firefox, Internet Explorer, Opera
 
|sdk= <!-- SDK(s) built and tested against (e.g. [http://linktosdkdownload/ Nokia Qt SDK 1.1]) -->
 
|sdk= <!-- SDK(s) built and tested against (e.g. [http://linktosdkdownload/ Nokia Qt SDK 1.1]) -->
 
|platform= Web browser
 
|platform= Web browser
 
|devicecompatability= <!-- Compatible devices e.g.: All* (must have internal GPS) -->
 
|devicecompatability= <!-- Compatible devices e.g.: All* (must have internal GPS) -->
|dependencies=Nokia Maps 2.2.3
+
|dependencies= HERE Maps 2.5.3
|signing=<!-- Signing requirements - empty or one of: Self-Signed, DevCert, Manufacturer -->
+
|signing= <!-- Signing requirements - empty or one of: Self-Signed, DevCert, Manufacturer -->
 
|capabilities= <!-- Capabilities required by the article/code example (e.g. Location, NetworkServices. -->
 
|capabilities= <!-- Capabilities required by the article/code example (e.g. Location, NetworkServices. -->
|keywords= Nokia Maps, JavaScript, Geocoordinates, onclick
+
|keywords= HERE Maps, JavaScript, Geocoordinates, onclick
|id= <!-- Article Id (Knowledge base articles only) -->
+
 
|language= <!-- Language category code for non-English topics - e.g. Lang-Chinese -->
 
|language= <!-- Language category code for non-English topics - e.g. Lang-Chinese -->
 
|translated-by= <!-- [[User:XXXX]] -->
 
|translated-by= <!-- [[User:XXXX]] -->
|translated-from-title= <!-- Title only -->  
+
|translated-from-title= <!-- Title only -->
 
|translated-from-id= <!-- Id of translated revision -->
 
|translated-from-id= <!-- Id of translated revision -->
|review-by=<!-- After re-review: [[User:username]] -->
+
|review-by= <!-- After re-review: [[User:username]] -->
 
|review-timestamp= <!-- After re-review: YYYYMMDD -->
 
|review-timestamp= <!-- After re-review: YYYYMMDD -->
 
|update-by= [[User:avnee.nathani]]
 
|update-by= [[User:avnee.nathani]]
 
|update-timestamp= 20120106
 
|update-timestamp= 20120106
|creationdate=20110621
+
|creationdate= 20110621
|author=[[User:Maveric]]
+
|author= [[User:Maveric]]
 
}}
 
}}
 
{{SeeAlso|
 
{{SeeAlso|
*  [http://developer.here.net/javascript_api Nokia Maps API]
+
*  [http://developer.here.net/javascript_api HERE Maps API]
 +
* [http://heremaps.github.io/examples/index.html HERE Maps on Github]
 
* [http://developer.here.net/apiexplorer/examples/api-for-js/events/map-coordinate-on-click.html Coordinates on click]  }}
 
* [http://developer.here.net/apiexplorer/examples/api-for-js/events/map-coordinate-on-click.html Coordinates on click]  }}
  
 
==Prerequisites==
 
==Prerequisites==
  
Nokia Maps API supported web browser (basically any modern web browser). The example assumes you have already added the Nokia Maps to your web page as explained in the previous article [[Nokia Maps API - Add Maps To Any Web Page]]
+
HERE Maps API supported web browser (basically any modern web browser). The example assumes you have already added the HERE Maps to your web page as explained in the previous article [[HERE Maps API - Add Maps To Any Web Page]]
  
 
==Important note about maps credentials==
 
==Important note about maps credentials==
  
Nokia provides several services options within the Maps API offering. The service is free to use, but you must obtain and use authentication and authorization credentials to use the services. Please read the
+
Nokia provides several services options within the Maps API offering. The service is free to use, but you must obtain and use authentication and authorization credentials to use the services. Please read the
 
[http://developer.here.net/terms_conditions Terms and Conditions] and check the [http://developer.here.net/web/guest/plans Pricing Plans page]  to decide which business model best fits your needs. Authentication requires unique Maps API credentials, namely an AppId and a token. You can get these credentials free for free following the instructions  [http://developer.here.net/docs/maps_js/topics/credentials.html#acquiring-credentials here]
 
[http://developer.here.net/terms_conditions Terms and Conditions] and check the [http://developer.here.net/web/guest/plans Pricing Plans page]  to decide which business model best fits your needs. Authentication requires unique Maps API credentials, namely an AppId and a token. You can get these credentials free for free following the instructions  [http://developer.here.net/docs/maps_js/topics/credentials.html#acquiring-credentials here]
  
Line 44: Line 44:
 
<code javascript>pixelToGeo (coord) : nokia.maps.geo.Coordinate - this will translate a projected pixel coordinate into a GEO Coordinate.</code>
 
<code javascript>pixelToGeo (coord) : nokia.maps.geo.Coordinate - this will translate a projected pixel coordinate into a GEO Coordinate.</code>
  
We also need to use the {{Icode|EventListener()}} and {{Icode|addListener()}} method, which is defined by the Nokia Maps API reference as follows: {{Icode|addListener (type, listener, useCapture)}}  ObjectRegisters an event listener, depending on the {{Icode|useCapture}} parameter, on the capture phase of the event flow or its target and bubbling phases.
+
We also need to use the {{Icode|EventListener()}} and {{Icode|addListener()}} method, which is defined by the HERE Maps API reference as follows: {{Icode|addListener (type, listener, useCapture)}}  ObjectRegisters an event listener, depending on the {{Icode|useCapture}} parameter, on the capture phase of the event flow or its target and bubbling phases.
  
 
Parameters:
 
Parameters:
{String}          type             Specifies the event type associated with the event for which the user is registering.
+
{String}          type Specifies the event type associated with the event for which the user is registering.
{Function}        listener         The function to be called if the event occurs.
+
{Function}        listener The function to be called if the event occurs.
  
 
==Example code==
 
==Example code==
Line 55: Line 55:
  
 
<code javascript>
 
<code javascript>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+
function addClickListener(map){
<html xmlns="http://www.w3.org/1999/xhtml">
+
map.addListener("click", function (evt){
    <head>
+
alert("in EventListener");
      <title>Pixel to geocoordinate</title>
+
coordinate = map.pixelToGeo(evt.displayX, evt.displayY);
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+
alert("Adding a Marker at: "+ coordinate.toString());
      <script type="text/javascript"
+
map.objects.add(new nokia.maps.map.Marker(coordinate));
            src="http://api.maps.nokia.com/2.2.3/jsl.js" charset="utf-8">
+
});
        </script>
+
}
    </head>
+
</code>
    <body>
+
  
        <div id="mapContainer" style="z-index: -1; left:0px; top:0px; width: 100%; height: 80%; position: absolute;"></div>
 
        <script type="text/javascript">
 
/////////////////////////////////////////////////////////////////////////////////////
 
// Don't forget to set your API credentials
 
//
 
// Replace with your appId and token which you can obtain when you
 
// register on http://api.developer.nokia.com/
 
//
 
nokia.Settings.set( "appId", "YOUR APP ID GOES HERE");
 
nokia.Settings.set( "authenticationToken", "YOUR AUTHENTICATION TOKEN GOES HERE");
 
  
//
+
A working example can be found at:
/////////////////////////////////////////////////////////////////////////////////////
+
 
var map = new nokia.maps.map.Display(document.getElementById("mapContainer"), {'zoomLevel':4, 'center':[53.1, 15.1]});
+
http://heremaps.github.io/examples/examples.html#geocoordinate-on-click
+
var clicked_location = "";
+
var myContainer;
+
+
map.addListener("click", eventListener);  // add the listener for mouse click
+
+
map.set("baseMapType", map.NORMAL);
+
+
function eventListener(event){
+
    alert("in EventListener");
+
    clicked_location = map.pixelToGeo(event.displayX, event.displayY);
+
    alert(clicked_location.toString());
+
    alert("Adding a Marker there");
+
    add_Marker_where_clicked();
+
}
+
+
+
function add_Marker_where_clicked(){
+
    myMarker = new nokia.maps.map.Marker(clicked_location);
+
    map.objects.add(myMarker);
+
}
+
</script>
+
</body>
+
</html>
+
</code>
+
  
==For more on the Nokia Maps API==
+
==For more on the HERE Maps API==
  
Please check out the Nokia Maps API full documentation and API reference here:
+
Please check out the HERE Maps API full documentation and API reference here:
* [http://developer.here.net/javascript_api Nokia Maps API]
+
* [http://developer.here.net/javascript_api HERE Maps API]
  
 
You may also access the interactive API explorer
 
You may also access the interactive API explorer
 
* [http://developer.here.net/javascript_api_explorer API explorer]
 
* [http://developer.here.net/javascript_api_explorer API explorer]

Latest revision as of 18:18, 20 December 2013

This article explains how to convert a map screen's pixel to a geocoordinate. This is useful when we want to know the geocoordinates of the point user had clicked.

Article Metadata
Code ExampleTested with
Devices(s): Google Chrome, Mozilla Firefox, Internet Explorer, Opera
Compatibility
Platform(s): Web browser
Dependencies: HERE Maps 2.5.3
Article
Keywords: HERE Maps, JavaScript, Geocoordinates, onclick
Created: Maveric (21 Jun 2011)
Updated: avnee.nathani (06 Jan 2012)
Last edited: jasfox (20 Dec 2013)

Contents

[edit] Prerequisites

HERE Maps API supported web browser (basically any modern web browser). The example assumes you have already added the HERE Maps to your web page as explained in the previous article HERE Maps API - Add Maps To Any Web Page

[edit] Important note about maps credentials

Nokia provides several services options within the Maps API offering. The service is free to use, but you must obtain and use authentication and authorization credentials to use the services. Please read the Terms and Conditions and check the Pricing Plans page to decide which business model best fits your needs. Authentication requires unique Maps API credentials, namely an AppId and a token. You can get these credentials free for free following the instructions here

[edit] Implementation

To achieve what we are about to do, we will need to use a method called pixelToGeo(), definition below:

pixelToGeo (coord) : nokia.maps.geo.Coordinate - this will translate a projected pixel coordinate into a GEO Coordinate.

We also need to use the EventListener() and addListener() method, which is defined by the HERE Maps API reference as follows: addListener (type, listener, useCapture) ObjectRegisters an event listener, depending on the useCapture parameter, on the capture phase of the event flow or its target and bubbling phases.

Parameters: {String} type Specifies the event type associated with the event for which the user is registering. {Function} listener The function to be called if the event occurs.

[edit] Example code

This example will add a new eventListener on the map and register the "click" event to fire the function eventListener(). We will get the position user had clicked and this will be converted from a pixel projection coordinate to a geo.Coordinate. The result is sent to screen with JavaScript Alert() method. Remember to add in your own AppId and Token.

function addClickListener(map){
map.addListener("click", function (evt){
alert("in EventListener");
coordinate = map.pixelToGeo(evt.displayX, evt.displayY);
alert("Adding a Marker at: "+ coordinate.toString());
map.objects.add(new nokia.maps.map.Marker(coordinate));
});
}


A working example can be found at:

http://heremaps.github.io/examples/examples.html#geocoordinate-on-click

[edit] For more on the HERE Maps API

Please check out the HERE Maps API full documentation and API reference here:

You may also access the interactive API explorer

This page was last modified on 20 December 2013, at 18:18.
358 page views in the last 30 days.

Was this page helpful?

Your feedback about this content is important. Let us know what you think.

 

Thank you!

We appreciate your feedback.

×