Difference between revisions of "Linden Lab Official:Map API"

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{{Help/Box|Update notice|<b>We've made improvements and changes to the Map API, effective January 15, 2009.<br>Some information here may be out of date as we update this wiki with the changes. Thanks for your patience.</b>}}
{{Supported API}}
{{:API Portal/navigation|map}}
Extend the reach of your Web site into Second Life using the ''Second Life Map API'', which enables you to embed interactive Second Life maps directly into your web pages. These maps look and act much like Google Maps, except that, instead of the Earth, they display the topography of the Second Life virtual world. See http://maps.secondlife.com/ for an example.


When you use the Map API to embed Second Life maps on your site, your visitors can:


{{:API Portal/navigation}}
* Click and drag the mouse pointer to pan the map view up, down, left, and right.
__TOC__
 
== Getting Started ==
 
The Second Life Map API is a set of Javascript objects and functions that enable you to embed Second Life maps onto your web pages.  It is a purely client-side Javascript API.  If needed, you can also [[#Accessing_map_images_directly|directly access]] the map images. 
 
'''NOTE:'''
This API is still in beta.  URLs and API signatures may change.
 
=== Map UI features ===
 
The Map API enables you to create web pages that have Google Maps functionality, using maps of Second Life, rather than Earth.  In general, the default map interface looks like the diagram at right.
 
[[Image:Map ui cropped.png|right]]
 
The main map display area shows the current map area.  By default, the map provides the following features:
 
* Click anywhere on the map to open a "teleport" window that displays the name of the region where you clicked and a button you can click to launch Second Life and teleport to that location.
* Click and drag the mouse pointer to pan the map view up, down, left, and right.  If desired, you can [[Map_API_Advanced_Examples#Disabling_and_enabling_dragging|disable this behavior]].
* Double-click to zoom in by one level (power of two) and display the teleport window.
* Double-click to zoom in by one level (power of two) and display the teleport window.
* Use the mouse wheel to zoom in and out.  See [[#Zoom_levels|Zoom levels]] for more information about zoom levels.
* Click anywhere on the map to open a "teleport" window.
* Use the zoom and pan controls at upper left to zoom the view in and out and to pan the view up, down, left, and right.  If desired, you can easily [[Map_API_Advanced_Examples#Customizing_zoom_and_pan_controls|create your own custom zoom and pan controls]].
* Use the mouse wheel or pan controls to zoom in and out.
* Use the overview control to move the view around by clicking and dragging, or double-clicking.  Close the overview control by clicking on the diagonal arrow at the very bottom right of the map.  You can specify whether the map provides an overview control when you [[Map_API_Reference#MarkerOptions|create the map object]].
 
<br clear="all" />
 
[[Image:Teleport window.png|left]]
Clicking anywhere on the map opens a window,  such as the one shown at left, indicating the point on which you clicked.  Clicking on the teleport button in the window then starts the Second Life Viewer, automatically teleporting you to the window's location.
 
Double-clicking on the map zooms in one level and then opens a window, as if you had clicked.
<br clear="all" />
 
=== Using slurl.com and DirectSLurl ===
 
The website http://slurl.com uses the Map API to provide a mechanism to teleport directly to locations in Second Life from web pages.
 
For more information, see [[Using Second Life URLs (SLURLs)]].
 
=== Prerequisites ===
 
To use the Second Life Map API in a web page, you must first:
* [http://www.google.com/apis/maps/signup.html Sign up for a Google Maps API key].  This enables you to use the Google Maps API, which is required to use SLMAPI.  See the [http://code.google.com/apis/maps/documentation/ Google Maps API documentation] for more information.
* Add the [[#Common_HTML_header|common header code]] at the beginning of each HTML file.  This code loads the Google Maps and Webmap Javascript libraries, the Webmap cascading stylesheet (CSS), and some other basic code.
 
NOTE: In general, it is best to reference the Map API Javascript library and CSS files that are on http://slurl.com.  Although you can download these files locally and modify them for your own use, if Linden Lab updates or changes these files, your applications will not get the benefit and may even stop working properly. 
 
=== Common HTML header ===
 
To use the Map API, put the following lines at the beginning of each HTML page.  This includes:
* Statements to load the required Second Life Map API and Google Maps Javascript libraries.
* Link to the Webmap cascading style sheet.
* Style declaration for the map div element.  This defines the size and other layout attributes of the map display.
 
<pre>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script src="http://maps.google.com/maps?file=api&v=2&key={GOOGLE MAPS KEY}"
  type="text/javascript"></script>
<script src="http://slurl.com/_scripts/slmapapi.js" type="text/javascript"></script>
 
<link rel="stylesheet" type="text/css" href="http://slurl.com/_styles/MAIN.css" />
<style>
div#map-container {
      width: 500px;
      height: 500px;
}
</style>
...
</pre>
 
Replace {GOOGLE MAPS KEY} with you Google Maps Key.
 
All the examples also require additional script statements in the HTML header.
 
'''Stylesheet'''
 
To use your own stylesheet, just include it AFTER the Webmap CSS, for example:
 
<link rel="stylesheet" type="text/css" href="http://slurl.com/_styles/MAIN.css" />
<link rel="stylesheet" type="text/css" href="myStyleSheet.css" />
 
'''Body element'''
 
Use the following body element in your HTML document:
 
<body load="loadmap()" onunload="GUnload();">
...
 
The '''GUnload()''' function is a Google Maps API  function that reduces memory leaks, particularly with Internet Explorer.  For more information, see the [http://code.google.com/apis/maps/documentation/#Memory_Leaks Google Maps API documentation].
 
=== Browser compatibility ===
The Map API has been tested to work with the following browsers:
* Internet Explorer 6.0
* Internet Explorer 7.0
* Firefox 1.0 or greater
* Safari 2.0
 
Other browsers may work but little issues may appear. Unless otherwise noted, all features work in all supported browsers.
 
=== Comments and feedback ===
 
If you encounter problems or bugs or have feature requests, please email '''webmap@secondlife.com'''.
 
Happy coding from the Second Life Web team!
 
== Basic concepts ==
 
The Map API's fundamental class is [[Webmap_API_Reference#SLMap|SLMap]].  It is a Javascript object representing the map with a large number of methods, enabling you to zoom, pan the view, and so on.
 
Additionally, the API includes the following key classes:
* [[Webmap_API_Reference#Marker|Marker]] - represents an image to display at a specify (x,y) point on the map.  You provide a set of images to display at each zoom level.  Contains several event handlers and other properties.  See [[#Map_with_a_marker|Map with a marker]] for a basic example.
* [[Webmap_API_Reference#MapWindow|Window]] - represents a captioned balloon pointing to a specified map location.  See [[Webmap_API#Map_with_an_initial_open_window|Map with an initial open window]] for a basic example.
* [[Webmap_API_Reference#Img|Img]] and [[Webmap_API_Reference#Icon|Icon]] - represent an image to use for markers, controls, or in windows.
 
===About coordinates===
 
Map coordinates are based on the Second Life grid system for positioning regions.
 
[[Image:Webmap coords.jpg]]
 
As illustrated in the diagram above, the Map API maps the Second Life world to the upper right quadrant of the Google world map.  A large scaling value
called slGridEdgeSizeInRegions (equal to 2<sup>20</sup> or 1,048,576) defines the largest region coordinate at the top and far right edge of the displayed area.  This value creates a map area with room for one trillion sims.
 
The little blue square illustrates where the populated sims are in Second Life.
 
=== Zoom levels ===
There are eight zoom levels: one through eight, one being the closest and eight being the farthest. Each level zooms by a power of two. In other words, at zoom level five, each region is twice the width as it was at zoom level six.
 
== Basic Examples ==
 
=== Required image files ===
 
Some of the following examples use image files for markers.  To run the examples with the code as shown, download the image files and save them in the same directory as the example HTML files.  Alternatively, create the Img objects using the URLs listed in the table below that refer to the images stored on this wiki.
 
The following table lists the images used in the examples:
 
{| {{Prettytable}}
|-{{Hl2}}
! Image
! File name
! URL
 
|-
| [[Image:Yellow marker.gif]]
| Yellow marker.gif
| https://wiki.secondlife.com/w/images/2/23/Yellow_marker.gif
 
 
|-
| [[Image:Fountain.gif]]
|Fountain.gif
| https://wiki.secondlife.com/w/images/6/60/Fountain.gif
 
|-
| [[Image:Forsale.png]]
| Forsale.png
| https://wiki.secondlife.com/wiki/Image:Forsale.png
 
|-
|[[Image:Forsale-shadow.png]]
|Forsale-shadow.png
|https://wiki.secondlife.com/w/images/d/d9/Forsale-shadow.png
|}
 
=== Simple map ===
 
The first example is a map with basic panning and zooming capabilities.  When you are done, it will look as shown here.
 
[[Image:MapAPI ex1.png|thumb|right|Simple map]]
 
You can pan the map and zoom in and out.
 
To create this example, follow these steps:
 
# Add common HTML header code.
# Add HTML body element.
# Add '''loadmap()''' function.
# Save and test.
 
<br clear="all"/>
 
'''1. Add common HTML header'''
 
First, include the [[Webmap_API#Common_HTML_header|common header code]], required by all Webmap applications. 
 
<pre><nowiki>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script src="http://slurl.com/_scripts/slmapapi.js" type="text/javascript"></script>
<script src="http://maps.google.com/maps?file=api&amp;v=2&amp;key={GOOGLE MAPS KEY}" type="text/javascript"></script>
 
<link rel="stylesheet" type="text/css" href="http://slurl.com/_styles/MAIN.css" />
<style>
div#map-container {
      width: 500px;
      height: 500px;
}
</style>
...
</head>
</nowiki></pre>
 
Be sure to replace {GOOGLE MAPS KEY} with your Google Map key.
 
'''2. Add HTML body element'''
 
Next, add the HTML body element to contain your map. The body contains a Javascript onload event handler that calls the '''loadmap()''' function you will define in the next step.
 
<pre>
<body onload="loadmap()" onunload="GUnload()">
  <div id="map-container"></div>
</body>
</pre>
 
The div element is passed to the SLMap object constructor, using the  <code>document.getElementById('map-container')</code> DOM method call.
 
NOTE: If you want the position attribute of the div element to be absolute, either set it programmatically using Javascript or using the style attribute tag.  Setting the position attribute of this element in the CSS stylesheet will not work.
 
'''3. Add loadmap() function'''
 
The body element you just added has a Javascript event handler for the "onload" event, called when the browser initially loads the page.  You deifined this to call a '''loadmap()''' function.  Now, define that Javascript function in the head of your page (after the code that is already there), as follows:
 
<script>
function loadmap() {
  mapInstance = new SLMap(document.getElementById('map-container'));
  mapInstance.centerAndZoomAtSLCoord(new XYPoint(997, 1002), 3);
}
</script>
 
The first line defines a new Map object from the HTML div element.  The second line centers the map at a specific point, and zooms it to zoom level three.
 
'''4. Save and test'''
 
When you are done, save the file, and then load it into your web browser.  Try panning the map by clicking and dragging the mouse cursor; you can also pan by clicking on the arrow icons on the four sides.  Also try zooming the view in and out by clicking the "+" and "-" icons.
 
'''Complete source code'''
 
<pre>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script src="http://maps.google.com/maps?file=api&v=2&key=[GOOGLE MAPS KEY]" type="text/javascript"></script>
<script src="http://slurl.com/_scripts/slmapapi.js" type="text/javascript"></script>
 
<link rel="stylesheet" type="text/css" href="http://slurl.com/_styles/MAIN.css" />
<style>
div#map-container {
      width: 500px;
      height: 500px;
}
</style>
 
<script>
function loadmap() {
  mapInstance = new SLMap(document.getElementById('map-container'));
  mapInstance.centerAndZoomAtSLCoord(new XYPoint(997, 1002), 2);
}
</script>
 
</head>
<body onload="loadmap()" onunload="GUnload()">
<div id="map-container"></div>
</body>
</pre>
 
=== Map with a marker ===
 
[[Image:Map with Marker.png|thumb|right|Map with a marker]]
 
A ''marker'' is simply an image displayed at a specific location on the map.  The Map API enables you to define an image for each zoom level, so the marker can appear differently at each zoom level if you wish.
 
This example shows how to make a map with a marker. The code is the same as the first example, with with addition of some Javascript after the initialization of the map in the page's onload event handler function, '''loadmap()'''.
 
To use the code below verbatim, you must download the marker image as described in [[#Required_image_files|Required image files]]; you can also use the URL of the wiki image if you prefer. 
 
The code first creates the icon for the marker, then places it on the map at (997, 1002) at the welcome area fountain.  Because the same icon is specified for every zoom level, it appears the same size regardless of zoom level.


For more information, see [[Map API Introduction]].
<br clear="all"/>
<br clear="all"/>
<pre>
// Create the icons
var yellow_dot_image = new Img("Yellow_marker.gif", 9, 9);
var yellow_icon = new Icon(yellow_dot_image);
var all_images = [yellow_icon, yellow_icon, yellow_icon, yellow_icon, yellow_icon, yellow_icon];
// Create the marker
var marker = new Marker(all_images, new XYPoint(997, 1002));
mapInstance.addMarker(marker);
</pre>
In this example, clicking on the marker does nothing.  Subsequent examples illustrate adding some onClick behavior.
'''Source code'''
Replace the first line comment below with the [[Webmap_API#Common_HTML_header|common header code]].
<pre>
<!-- Insert common HTML header -->
<script>
function loadmap() {
  // creates the map
  var mapInstance = new SLMap(document.getElementById('map-container'));
  mapInstance.centerAndZoomAtSLCoord(new XYPoint(997, 1002), 2);
 
  // creates the icons
  var yellow_dot_image = new Img("Yellow_marker.gif", 9, 9);
  var yellow_icon = new Icon(yellow_dot_image);
  var all_images = [yellow_icon, yellow_icon, yellow_icon, yellow_icon, yellow_icon, yellow_icon];
 
  // creates the marker
  var marker = new Marker(all_images, new XYPoint(997, 1002));
  mapInstance.addMarker(marker);
}
</script>
</head>
<body onload="loadmap()" onunload="GUnload()">
<p>There should be a yellow marker in the center of this map:
<div id="map-container"></div>
</body>
</pre>
=== Map with an initial open window ===
[[Image:Map_with_window.png|thumb|right|Map with a window]]
A Webmap ''window'' is a caption pointing to a specific point on the map, as shown in the screenshot at right.  It looks something like a comic book dialog bubble. 
Use the [[Webmap_API_Reference#MapWindow|MapWindow]] object to create a window.
For example, to create a window that opens initially when the page loads:
# Instantiate a [[Webmap_API_Reference#MapWindow|MapWindow]] object with the desired caption.
# Call the '''addMapWindow()''' method on the [[Webmap_API_Reference#SLMap|SLMap]] object to add the window to the map.
<br clear="all"/>
For example:
<pre>
// creates a window
var mapWindow = new MapWindow("This is where the welcome area fountain is!!");
mapInstance.addMapWindow(mapWindow, new XYPoint(997, 1002));
</pre>
The code adds an open window to the map positioned again at (997, 1002), right above the welcome area fountain.
NOTE: after the user closes the window there is no way to bring it back.  A subsequent example will show how to enable the user to reopen the window, by using markers with windows.
<br clear="all"/>
To make the map initially centered on the fountain, change the call to '''centerAndZoomAtSLCoord()''' as follows:
  mapInstance.centerAndZoomAtSLCoord(new XYPoint(997, 1002), 3);
'''Source code'''
This example shows how to create a map with a window. The code is the same as the first example, with the addition of some lines of Javascript after the initialization of the map, in the '''loadmap()''' function. In addition, the map is centered in a different location in order to make the window fully visible.
Replace the first line comment below with the [[Webmap_API#Common_HTML_header|common header code]].
<pre>
<!-- Insert common HTML header -->
<script>
function loadmap() {
  mapInstance = new SLMap(document.getElementById('map-container'));
  mapInstance.centerAndZoomAtSLCoord(new XYPoint(997, 1002), 3);
 
  // Create window
var mapWindow = new MapWindow("This is where the welcome area fountain is!!");
mapInstance.addMapWindow(mapWindow, new XYPoint(997, 1002));
}
</script>
</head>
<body onload="loadmap()" onunload="GUnload()">
  <h1>Simple Map Example</h1>
  <div id="map-container"></div>
</body>
</pre>
=== Map with a marker that opens a window ===
[[Image:Map with marker and window.png|thumb|right|Map with marker that opens a window]]
This example shows how to create a map with a marker which opens a window when clicked.  It is a combination of the previous two examples, because the code first creates a marker and a window. 
The difference comes in adding the marker to the map: this time you provide the window object as well as the marker object in the call to '''addMarker()''':
mapInstance.addMarker(marker, mapWindow);
Doing this adds the marker and causes it to open the specified window when the user clicks it.  If the user subsequently closes the window, s/he can open it again by clicking on the marker.
<br clear="all" />
'''Source code'''
Replace the first line comment below with the [[Webmap_API#Common_HTML_header|common header code]].
<pre>
<!--- Insert common HTML header --->
<script>
function loadmap() {
  // Create the map
  var mapInstance = new SLMap(document.getElementById('map-container'));
  mapInstance.centerAndZoomAtSLCoord(new XYPoint(997.5, 1001.5), 2);
 
  // Create the icons
  var yellow_dot_image = new Img("Yellow_marker.gif", 9, 9);
  var yellow_icon = new Icon(yellow_dot_image);
  var all_images = [yellow_icon, yellow_icon, yellow_icon, yellow_icon, yellow_icon, yellow_icon];
 
  // Create the marker
  var marker = new Marker(all_images, new XYPoint(997, 1002));
 
  // Create a window
  var mapWindow = new MapWindow("This is where the welcome area fountain is!! <br><img src='Fountain.gif'>");
 
  // Adds the marker to the map
  mapInstance.addMarker(marker, mapWindow);
}
</script>
</head>
<body onload="loadmap()" onunload="GUnload()">
<p>This map shows a yellow marker on the welcome fountain.  When you click the marker,
a window appears with a screenshot of the fountain.</p>
<div id="map-container"></div>
</body>
</pre>
== Accessing map images directly ==
The Second Life map images are stored on [http://aws.amazon.com/s3/ Amazon Simple Storage Service (Amazon S3)].  You can access the map images directly on the Amazon S3 servers using the following URL format:
<nowiki>http://map.secondlife.com/Z/XXXXX/YYYYY/map-Z-X-Y-objects.jpg</nowiki>
Where:
* Z - Zoom level desired:
** One (1) is the most zoomed-in view, showing individual region tiles.
** Eight (8) is the maximum zoom level, showing the entire world.
* X,Y - X and Y coordinates on the Second Life Grid of the region, for example, region Ahern is (997,1002).  In the "directory path" (not the file name), pad the coordinate values to five characters with leading zeros; so for the previous coordinates, the path would be "00997/01002".
Tiles with zoom greater than one are stored at the lower left corner coordinate of the tiles that are included in the image.
In other words, you can find the zoom tile containing region (X,Y) for zoom level Z at the directory Z/X'/Y' where:
X' = X - (X % (2<sup>Z - 1</sup>) )
and
Y' = Y - (Y % (2<sup>Z - 1</sup>) )
Note that 2<sup>Z - 1</sup> is the number of regions encompassed by the width of a tile at resolution Z.
=== Examples ===
For example: if Z = 1, the four region tiles are:
* http://map.secondlife.com/1/01000/01000/map-1-1000-1000-objects.jpg
* http://map.secondlife.com/1/01001/01000/map-1-1001-1000-objects.jpg
* http://map.secondlife.com/1/01000/01001/map-1-1000-1001-objects.jpg
* http://map.secondlife.com/1/01001/01001/map-1-1001-1001-objects.jpg
These four region tiles are compressed into the single tile:
http://map.secondlife.com/2/01000/01000/map-2-1000-1000-objects.jpg
The following shows the map zoomed all the way out, showing the entire Second Life world view:
http://map.secondlife.com/8/01024/00896/map-8-1024-896-objects.jpg
The following displays a single tile contained in the view above, zoomed all the way in:
http://map.secondlife.com/1/01027/01019/map-1-1027-1019-objects.jpg
===Implementation notes=== 
The map generation process is more scalable than the previous release, and is able to image the entire Second Life grid of about 30,000 regions in less than two days. 
There is a "decay period" for offline regions. If a region is disabled, the tile will stay up for several days (in case it comes back or something else has gone wrong) before the tile disappears. That several-day period will be longer than the time it takes to update existing regions or put new regions on the map.
=== Getting a map URL from LSL ===
The following LSL script illustrates how to display a map of the current region to an avatar:
<lsl>
ShowMap(key avatar) {
    string url = "http://map.secondlife.com.s3.amazonaws.com/1/";
    vector sim_coord = llGetRegionCorner();
    string x = (string)((integer)(sim_coord.x / 256.0));
    string y = (string)((integer)(sim_coord.y / 256.0));
    string x0 = llStringTrim(llGetSubString(" 00000", 0, 5 - llStringLength(x)), STRING_TRIM_HEAD) + x;
    string y0 = llStringTrim(llGetSubString(" 00000", 0, 5 - llStringLength(y)), STRING_TRIM_HEAD) + y;
    url += x0 + "/" + y0 + "/" + "map-1-" + x + "-" + y + "-objects.jpg";
    llLoadURL(avatar, "View the sim map", url);
}
</lsl>
Contributed under GPL v3 license by [[User:Henri Beauchamp|Henri Beauchamp]] 09:00, 24 January 2009 (UTC)
== Release notes ==
This section describes new features and known issues with the current release of the Map API.  See also [http://blog.secondlife.com/2009/01/22/improvements-to-mapping-and-upgrade-to-slurlcom/ Philip Linden's blog post announcement].
The current release of the Map API was release on Jan 15, 2009.
=== New features ===
This release of the Map API provides significant performance improvements over the previous release, including:
* Map loads faster and operates more smoothly.
* Map images are updated more accurately and rapidly.  Changes to the Second Life Grid or content will now be visible within about two days. 
* Map images look smoother and are more accurate when compared to the actual in-world content.
Changes in functionality:
* You can now single-click on any location on the map and teleport directly there. 
* Zoom levels go up to eight, so you can now zoom out and see how big SL has really become!
* More intuitive map tile image file naming convention.
The Map API now gets map tile images directly from [http://aws.amazon.com/s3/ Amazon S3], and the file naming convention will make it easier to develop other third party maps based on the tiles we are generating.

Latest revision as of 13:27, 4 May 2011

NOTE: This is an official Second Life API provided and documented by Linden Lab. Its use is subject to the API Terms of Use.

Extend the reach of your Web site into Second Life using the Second Life Map API, which enables you to embed interactive Second Life maps directly into your web pages. These maps look and act much like Google Maps, except that, instead of the Earth, they display the topography of the Second Life virtual world. See http://maps.secondlife.com/ for an example.

When you use the Map API to embed Second Life maps on your site, your visitors can:

  • Click and drag the mouse pointer to pan the map view up, down, left, and right.
  • Double-click to zoom in by one level (power of two) and display the teleport window.
  • Click anywhere on the map to open a "teleport" window.
  • Use the mouse wheel or pan controls to zoom in and out.

For more information, see Map API Introduction.

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