Tutorial 2: Making Embeded WWJava Zoom to a Location
Written by Chad on August 10th, 2008
In Tutorial 1, we went into just how to embed a WWJava applet into a web page. In this tutorial I will expand the scope and use Javascript to make the globe move to a preset location after the applet loads. Note: I have noticed a bug while working on this tutorial with Firefox 3.x. Javascript interaction with the WWJava globe does not seem to work. It did work in FF 2.x, I am not sure if it is a FF issue or a WWJava issue though.
First off open up your web page that has the WWJava applet code in and we will be adding the following Javascript to it:
<script language="javascript">
<!--
// Author: Patrick Murris
// Version:
// Applet init, start and stop - called from java at the end of applet init() and start()
// and at the begining of stop()
function appletInit() {
}
function appletStart() {
// Fly to a location after a delay
setTimeout("startup()", 5000); // 5 seconds
}
This part of the code starts the startup function after a delay of 5 seconds.
function startup() {
// Move to show overview
gotoLocation(GOTO_OVERVIEW);
}
In this tutorial, startup will be calling the gotoLocation function, this loads the function and also the variable that defines what the goto location is.
function appletStop() {
}
var GOTO_OVERVIEW = "Detroit;42.46;-83.16;260000;0;40";
This is where you define your zoom to location.
Location strings contain the following information separated by ‘;’:
- name displayed on the globe
- latitude in decimal degrees
- longitude in decimal degrees
- eye distance from location in meters
- heading angle in decimal degrees, clockwise from north
- pith angle from vertical in decimal degrees
function gotoLocation(locationString) {
var params = locationString.split(';');
if(params.length == 3) // Lat/lon
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]));
else if(params.length == 4) // Lat/lon and zoom
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]), parseFloat(params[3]), 0, 0);
else if(params.length == 5) // Lat/lon/zoom and heading
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]), parseFloat(params[3]), parseFloat(params[4]), 0);
else if(params.length == 6) // Lat/lon/zoom/heading and pitch
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]), parseFloat(params[3]), parseFloat(params[4]), parseFloat(params[5]));
}
// -->
</script>
This function is what processes the goto location values and then displays the location on the WWJava globe.
This is the finished HTML page now:
<html>
<head>
<title>NASA World Wind Java Applet</title>
</head>
<script language="javascript">
<!--
// Author: Patrick Murris
// Version:
// Applet init, start and stop - called from java at the end of applet init() and start()
// and at the begining of stop()
function appletInit() {
}
function appletStart() {
// Fly to a location after a delay
setTimeout("startup()", 5000); // 5 seconds
}
function startup() {
// Move to show overview
gotoLocation(GOTO_OVERVIEW);
}
function appletStop() {
}
var GOTO_OVERVIEW = "Detroit;42.46;-83.16;260000;0;40";
function gotoLocation(locationString) {
var params = locationString.split(';');
if(params.length == 3) // Lat/lon
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]));
else if(params.length == 4) // Lat/lon and zoom
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]), parseFloat(params[3]), 0, 0);
else if(params.length == 5) // Lat/lon/zoom and heading
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]), parseFloat(params[3]), parseFloat(params[4]), 0);
else if(params.length == 6) // Lat/lon/zoom/heading and pitch
document.getElementById('wwjApplet').getSubApplet().gotoLatLon(parseFloat(params[1]), parseFloat(params[2]), parseFloat(params[3]), parseFloat(params[4]), parseFloat(params[5]));
}
// -->
</script>
<body>
<applet id="wwjApplet" name="wwjApplet" mayscript code="org.jdesktop.applet.util.JNLPAppletLauncher" width=600 height=380
archive="applet-launcher.jar, http://worldwind.arc.nasa.gov/java/demos/worldwind.jar, WWJApplet.jar, http://download.java.net/media/jogl/builds/archive/jsr-231-webstart-current/jogl.jar, http://download.java.net/media/gluegen/webstart/gluegen-rt.jar">
<param name="codebase_lookup" value="false" />
<param name="subapplet.classname" value="gov.nasa.worldwind.examples.applet.WWJApplet" />
<param name="subapplet.displayname" value="WWJ Applet" />
<param name="noddraw.check" value="true" />
<param name="progressbar" value="true" />
<param name="jnlpNumExtensions" value="1" />
<param name="jnlpExtension1" value="http://download.java.net/media/jogl/builds/archive/jsr-231-webstart-current/jogl.jnlp" />
</applet>
</body>
</html>
The output looks like this:
wwJava applet first loaded
Globe zooming into the defined location after 5 seconds
Final stopping point
10
PM
Thank you for this tutorial series!
Some issues I had below:
Tutorial 1: zoom doesn’t work in Safari using imac’s mightymouse scroll ball. It works OK in Firefox 3.0
Tutorial 2: zoom to location doesn’t work in Firefox 3.0
Some questions:
1. Where do wwjava save my cache of downloaded images?
Future request:
1. Add wms layers. I have a local wms for our project and it would be good to add them to wwjava.
Looking forward for the succeeding tutorials.
cheers,
maning
10
PM
Not sure on your first bug you found, I can try on a macbook pro tomorrow (closest I have). As for the second bug, already know that one (mentioned it in the post even). I am asking the WW devs if this would be FF or a WWJava bug.
For your feature request, check out the NASA WWJava demo page
Should have two or three more basic demos for sure.
11
AM
Interesting tutorial indeed, thanks!
Is it possible to embed WWJ in a WinForms application? (So as to avoid the headaches of WW.NET).
11
AM
Dimitris: I want to say “yes” but I am not 100% sure.. I think that was asked on the WorldWind forums before. But the best place for your questions would be there.
13
AM
Thank you. I found the relevant thread.
5
AM
just wanna be