Cl PA 2003 XIX 11 ' International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
A URL can reference images in the SVG image tag like in 
HTML. The image tag imports the file at the position x, y. The 
size is defined by the parameters width and height. 
<image xlink:href="wagenhaus.gif" x="580" 
y="380" width="64" height="32"> 
<set attributeName="opacity" 
attriuteType="CSS" to="1.0 
begin="mouseover"/> 
<set attributeName="opacity" 
attriuteType="CSS" to="0.2" 
begin="mouseout"/> 
</image> 
Furthermore there are two events announced. In one case the 
opacity is set to 1.0 in the other case the value is set to 0.1. The 
events will be initialised while touching the image with the 
mouse (mouseover) or while leaving the image (mouseout). 
This example is used in the following mapping application for 
displaying views of buildings in transparency or full colour 
while touched by the pointing device. 
5 MAPPING APPLICATION 
Building an interactive VR world in an immersive environment 
is projected in co-operation between Preussen-Museum, Minden 
and University of Applied Sciences, Bielefeld. Some studies of 
access to VRML models and interactivity are already discussed. 
Here a suggestion is submitted to implement an interactive map 
for investigating the past and the future of the area named Sime- 
onsplatz. The sample can be visited under www.divide-by- 
zero.com/svg/simeonsplatz.svg. This file is in a very early state 
and for the time being not optimised. But hints to possibilities 
for final implementation can be read from this example. A 
screenshot is displayed in figure 4. 
The simple file structure as an extract from the complete code is 
demonstrated here. The optimised file with referenced tree 
symbols by the <use> tag and <text> tags will be around 90 
kByte. 
<?xml version="1.0" encoding="UTF-8"?> 
<svg width="1200.0" height="830.232" 
viewBox="75.0 50.0 1032.000 714.000"> 
<title>Simeonsplatz in Minden</title> 
<desc>CADConverter + Editor</desc> 
<defs> 
<!-- definitions --> 
</defs> 
<g id="legend"> 
<text x="480" y="93" 
text-anchor="middle" 
font-size="16" font-family="Verdana" 
fill="black" 
stroke="black" stroke-width="0.1"> 
Simeonsplatz in Minden</text> 
erect x="87" y="62" width="24" 
height="8" 
fill="rgb(128,128,128)" stroke="black" 
stroke-width="0.2"/> 
<!— other graphics for the legend --> 
</g> 
<g id="surfaces"> 
<path d="M227.63 364.08L231.96 369.64 
<!-- graphics for surfaces --> 
fill="rgb (216, 192, 177)" 
stroke="rgb(216,192,177)" 
stroke-width="0.2"/> 
</g> 
<desc>image reference to Schwichow- 
Denkmal</desc> 
eimage xlink:href="schwichow_denkmal.gif" 
x="400" 
y="120" width="32" height="32"> 
<set attributeName="opacity" 
attributeType="CSS" 
to="1.0" begin="mouseover"/> 
<set attributeName="opacity" 
attributeType="CSS" 
to="0.2" begin="mouseout"/> 
</image> 
<g id="wagenhaus"> 
<a xlink:href="wagenhaus.wrl" 
target="_blank"> 
<! graphic embedded in a link --> 
</a> 
</g> 
<g id="buildings"> 
<!-- other buildings, not of particula 
interest --> 
</g> 
<g id="trees"> 
<!-- the trees, should be referenced --> 
</g> 
<g id="text"> 
<!-- text for the drawing --> 
</g> 
<!-- Please note: SVG renders --> 
<!-- like the painter algorithm --> 
<!-- The element coming in last --> 
<!-- is visible in front of --> 
<!-- others behind. --> 
</svg>