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HERE Maps API - How to change map zoom level and center point

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[[Category:Nokia Maps]][[Category:Code Snippet]][[Category:JavaScript]]
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[[Category:HERE Maps]][[Category:JavaScript]][[Category:Code Examples]]
 
{{Abstract|This article explains how to change map zoom level and map center. }}
 
{{Abstract|This article explains how to change map zoom level and map center. }}
  
{{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/map-set-center-and-zoom-level.html map-set-center-and-zoom-level.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= Internet Explorer, Google Chrome, Firefox, Opera
 
|devices= Internet Explorer, Google Chrome, Firefox, Opera
Line 9: Line 9:
 
|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, Zoom, Component, Components, center, centre
+
|keywords= HERE Maps, JavaScript, Zoom, Component, Components, center, centre
|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]]
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|update-by= [[User:avnee.nathani]]
|update-timestamp=20111231
+
|update-timestamp= 20111231
|creationdate=20110621
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|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]
* [[Nokia Maps API - Add Maps To Any Web Page|Add Maps To Any Web Page]]
+
* [[HERE Maps API - Add Maps To Any Web Page|Add Maps To Any Web Page]]
* [[Nokia Maps API - Geocoordinate system|The Geocoordinate system]]
+
* [[HERE Maps API - Geocoordinate system|The Geocoordinate system]]
 
* [http://developer.here.net/apiexplorer/examples/api-for-js/map/zooming-the-map.html Zooming the Map]
 
* [http://developer.here.net/apiexplorer/examples/api-for-js/map/zooming-the-map.html Zooming the Map]
 
* [http://developer.here.net/apiexplorer/examples/api-for-js/map/panning-the-map.html Panning the Map]
 
* [http://developer.here.net/apiexplorer/examples/api-for-js/map/panning-the-map.html Panning the Map]
Line 37: Line 36:
 
==Prerequisites==
 
==Prerequisites==
  
Nokia Maps API supported web browser (basically any modern web browser)
+
HERE Maps API supported web browser (basically any modern web browser)
  
 
==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]
  
 
==Implementation==
 
==Implementation==
  
You can change the parameters for the map view by passing them to your map instance (handled in the article "[[Nokia Maps API - Add Maps To Any Web Page|Add Maps To Any Web Page]]") that define the zoom level and center point for the map can be set to suit your purposes. The map will default in our example to Berlin, Germany but you can of course change the center to point to any other location on this planet.
+
You can change the parameters for the map view by passing them to your map instance (handled in the article "[[HERE Maps API - Add Maps To Any Web Page|Add Maps To Any Web Page]]") that define the zoom level and center point for the map can be set to suit your purposes. The map will default in our example to Berlin, Germany but you can of course change the center to point to any other location on this planet.
  
 
==Map centre==
 
==Map centre==
Line 76: Line 75:
 
The coordinate represents a geographical position. Altitude is defined as optional. (For more details on this see the Maps API reference).
 
The coordinate represents a geographical position. Altitude is defined as optional. (For more details on this see the Maps API reference).
  
Note: There is an article about the  [[Nokia Maps API - Geocoordinate system|The coordinate system and geocoordinates]]. You may want to check it out for more detailed information on the geocoordinate system used in Nokia Maps and some generic information about the world coordinate system.
+
Note: There is an article about the  [[HERE Maps API - Geocoordinate system|The coordinate system and geocoordinates]]. You may want to check it out for more detailed information on the geocoordinate system used in HERE Maps and some generic information about the world coordinate system.
  
In our example we will use the latitude and longitude values for the city of D&uuml;sseldorf, Germany : 51.233333&deg;N, 6.783333&deg;E These will be passed in the form {{Icode|[51.233333, 6.783333]}}.  
+
In our example we will use the latitude and longitude values for the city of D&uuml;sseldorf, Germany : 51.233333&deg;N, 6.783333&deg;E These will be passed in the form {{Icode|[51.233333, 6.783333]}}.  
 
The latitude and longitude can be passed as a floating point number, i.e. {{Icode|13.4}} is just as valid as e.g. {{Icode|13.456789}}
 
The latitude and longitude can be passed as a floating point number, i.e. {{Icode|13.4}} is just as valid as e.g. {{Icode|13.456789}}
  
 
==ZoomLevel==
 
==ZoomLevel==
  
The Nokia Maps {{Icode|ZoomLevel}} is a number between the minimum and maximum zoom values and can be queried with the {{Icode|minZoomLevel()}} and {{Icode|maxZoomLevel()}} methods.  
+
The HERE Maps {{Icode|ZoomLevel}} is a number between the minimum and maximum zoom values and can be queried with the {{Icode|minZoomLevel()}} and {{Icode|maxZoomLevel()}} methods.  
  
 
At the moment, the API offers zoom levels between 0 (zero) and 20. This is reflected by the UI Zoom Bar on the Map view. The zoom levels that the UI Zoom Bar uses are:
 
At the moment, the API offers zoom levels between 0 (zero) and 20. This is reflected by the UI Zoom Bar on the Map view. The zoom levels that the UI Zoom Bar uses are:
  
Level     Name <br />
+
Level Name <br />
14         Street  <br />
+
14 Street  <br />
11         City <br />
+
11 City <br />
8         County <br />
+
8 County <br />
3         Country <br />
+
3 Country <br />
  
 
How to request the min and max zoom levels of the current map:
 
How to request the min and max zoom levels of the current map:
Line 102: Line 101:
 
==Example code==
 
==Example code==
  
We are using the same code as in the [[Nokia Maps API - Add Maps To Any Web Page|Add Maps To Any Web Page]] example, simply changing the {{Icode|zoomLevel}} and  {{Icode|center}}. Remember to add in your own [[How to Obtain Your Own Nokia appID and Token| AppId and Token]].
+
After setting up the same code as in the [[HERE Maps API - Add Maps To Any Web Page|Add Maps To Any Web Page]] example, simply call the function defined below:
  
 
<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 setCenterAndZoom(map){
<html xmlns="http://www.w3.org/1999/xhtml">
+
map.set('zoomLevel', 10);
    <head>
+
map.set('center', [51.23, 6.78]);
      <title>Map of D&uuml;sseldorf</title>
+
}
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+
      <script type="text/javascript"
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            src="http://api.maps.nokia.com/2.2.3/jsl.js" charset="utf-8">
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        </script>
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    </head>
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    <body>
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        <h1>Map of D&uuml;sseldorf</h1>
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        <div id="map" style="z-index: -1; left:0px; top:0px; width: 100%; height: 80%; position: absolute;"></div>
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        <script type="text/javascript">
+
/////////////////////////////////////////////////////////////////////////////////////
+
// Don't forget to set your API credentials
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//
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// Replace with your appId and token which you can obtain when you
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// register on http://api.developer.nokia.com/
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//
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nokia.Settings.set( "appId", "YOUR APP ID GOES HERE");
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nokia.Settings.set( "authenticationToken", "YOUR AUTHENTICATION TOKEN GOES HERE");
+
+
//
+
/////////////////////////////////////////////////////////////////////////////////////
+
            var map = new nokia.maps.map.Display(document.getElementById("map"),{
+
'zoomLevel': 8,                         // Country level
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'center': [51.233333, 6.783333]                 // New map center point
+
});  
+
        </script>
+
    </body>
+
</html>
+
 
</code>
 
</code>
  
 
When you have defined these, the map should open on Country level zoom, with the city of D&uuml;sseldorf, Germany in the middle of the map view.
 
When you have defined these, the map should open on Country level zoom, with the city of D&uuml;sseldorf, Germany in the middle of the map view.
 +
 +
[[File:setCenterAndZoomLevel.png]]
 +
 +
A working example can be found at:
 +
 +
http://rawgithub.com/heremaps/examples/master/maps_api_for_javascript/simple-examples/map-set-center-and-zoom-level.html
  
 
==Zoom level==
 
==Zoom level==
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<code java>
 
<code java>
Level     Name
+
Level Name
14         Street   
+
14 Street   
11         City
+
11 City
8         County
+
8 County
3         Country
+
3 Country
 
</code>
 
</code>
  
Line 164: Line 142:
 
</code>
 
</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]
 +
 +
And additional examples on GitHub
 +
* [http://heremaps.github.io/examples/ HERE Maps on Github]

Latest revision as of 17:27, 12 March 2014

This article explains how to change map zoom level and map center.

Article Metadata
Code ExampleTested with
Devices(s): Internet Explorer, Google Chrome, Firefox, Opera
Compatibility
Platform(s): Web browser
Dependencies: HERE Maps 2.5.3
Article
Keywords: HERE Maps, JavaScript, Zoom, Component, Components, center, centre
Created: Maveric (21 Jun 2011)
Updated: avnee.nathani (31 Dec 2011)
Last edited: jasfox (12 Mar 2014)


Contents

[edit] Prerequisites

HERE Maps API supported web browser (basically any modern web browser)

[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

You can change the parameters for the map view by passing them to your map instance (handled in the article "Add Maps To Any Web Page") that define the zoom level and center point for the map can be set to suit your purposes. The map will default in our example to Berlin, Germany but you can of course change the center to point to any other location on this planet.

[edit] Map centre

The centre of the map is defined by the center property and is defined by a nokia.maps.geo.Coordinate

Constructor detail:
 
The coordinate represents a geographical position. As most of the use cases currently do not consider height information,
the altitude is defined as optional. If a corresponding type is already provided by the platform the product must not implement this class.
new nokia.maps.geo.Coordinate(lat, lng, [alt, [skipValidation]])
 
Parameters:
{Number} lat //Latitude in degrees. -90 <= latitude <= 90. Values outside of range throw an {{Icode| IllegalArgument}} error.
{Number} lng // Longitude in degrees. -180 <= longitude <= 180. Values outside of range throw an {{Icode| IllegalArgument}} error.
{Number} [alt]: undefined // Altitude in meters.
{Boolean} [skipValidation]: false //If true, the validation of the latitude, longitude and altitude values is skipped.

We will create a new Coordinate, but will leave out altitude, and we want the values to be validated, so we will leave the skipValidation to it's default value.


new nokia.maps.geo.Coordinate (lat, lng, [alt, [skipValidation]])

The coordinate represents a geographical position. Altitude is defined as optional. (For more details on this see the Maps API reference).

Note: There is an article about the The coordinate system and geocoordinates. You may want to check it out for more detailed information on the geocoordinate system used in HERE Maps and some generic information about the world coordinate system.

In our example we will use the latitude and longitude values for the city of Düsseldorf, Germany : 51.233333°N, 6.783333°E These will be passed in the form [51.233333, 6.783333]. The latitude and longitude can be passed as a floating point number, i.e. 13.4 is just as valid as e.g. 13.456789

[edit] ZoomLevel

The HERE Maps ZoomLevel is a number between the minimum and maximum zoom values and can be queried with the minZoomLevel() and maxZoomLevel() methods.

At the moment, the API offers zoom levels between 0 (zero) and 20. This is reflected by the UI Zoom Bar on the Map view. The zoom levels that the UI Zoom Bar uses are:

Level Name
14 Street
11 City
8 County
3 Country

How to request the min and max zoom levels of the current map:

map.minZoomLevel   // Could return for example "0" (zero)
map.maxZoomLevel // Could return for example "20"

[edit] Example code

After setting up the same code as in the Add Maps To Any Web Page example, simply call the function defined below:

function setCenterAndZoom(map){
map.set('zoomLevel', 10);
map.set('center', [51.23, 6.78]);
}

When you have defined these, the map should open on Country level zoom, with the city of Düsseldorf, Germany in the middle of the map view.

SetCenterAndZoomLevel.png

A working example can be found at:

http://rawgithub.com/heremaps/examples/master/maps_api_for_javascript/simple-examples/map-set-center-and-zoom-level.html

[edit] Zoom level

zoomLevel - The map zoom level is defined by this property

The zoomLevel is a number between minimum and maximum values and can be queried with the minZoomLevel() and maxZoomLevel() methods.

At the moment, the API offers zoom levels between 0 (zero) and 20. This is reflected by the UI component ZoomBar on the Map view. The zoom levels used by the UI map zoom component are:

Level Name
14 Street
11 City
8 County
3 Country

How to request the min and max zoom levels of the current map:

map.minZoomLevel   <-  Could return example "0" (zero)
map.maxZoomLevel <- Could return example "20"

[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

And additional examples on GitHub

This page was last modified on 12 March 2014, at 17:27.
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