Mapping Hacks

Plot Points on a Spinning Globe Applet #40

Chapter 4, Mapping (on) the Web

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181

HACK

You can either display the applet’s internal Unzoom button by adding this

param to the applet tag in the HTML file:

<param name="showzoomoutbutton" value="true">

which adds a not very attractive but perfectly functional Unzoom button to

the applet.

Or you can use JavaScript to call the applet’s

zoomFullOut( ) method. This

allows you to use a button or image of your choice on the web page, outside

of the applet’s area, to Unzoom, giving you better control of the look of your

page. For example:

<img src="unzoom.png" onClick="document.Globe.zoomFullOut( )"/>

If you use the previous sample XML, when you load the applet page you’ll

see only London and Amsterdam pinpoints. This is because they belong to

group1, which was the only group with the attribute on="true".

How do you allow the user to choose whether or not to display specific

groups? Use JavaScript to call the applet’s

displayGroup(groupName,boolean)

method. For example:

<form name="groupdisplay">

<!--Display Group 1:-->

<input type="checkbox" name="group1" CHECKED onClick="document.Globe.

displayGroup('group1',document.groupdisplay.group1.checked)"/><br/>

<!--Display Group 2:-->

<input type="checkbox" name="group2" onClick="document.Globe.

displayGroup('group2',document.groupdisplay.group2.checked)"/><br/>

<!--Display Group 3:-->

<input type="checkbox" name="group3" ...