Thanks for the clarification :)<br><br><div><span class="gmail_quote">On 8/14/06, <b class="gmail_sendername">Fawcett, David</b> <<a href="mailto:David.Fawcett@state.mn.us">David.Fawcett@state.mn.us</a>> wrote:</span>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div>
<div>
<div><span><font color="#0000ff" face="Arial" size="2">I
would say that zoom is still meaningful in describing MapServer. When you
'zoom', you either request a layer that shows more (or less) earth area in your
fixed-size map window. </font></span></div>
<div><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div><span><font color="#0000ff" face="Arial" size="2">Overviews do not relate directly to the map image being returned by
MapServer. They are used as part of a raster data source to help make your
application more efficient. An overview is useful when you have images
that have a high resolution and you want to use as a data layer on a relatively
low resolution map. </font></span></div>
<div><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div><span><font color="#0000ff" face="Arial" size="2">For
example, if you have an air photo that is 1,000,000 x 1,000,000 pixels and you
want to use it at full extent in your map image that is 100 x 100 pixels.
Every time that you request a map image, MapServer or one of it's components has
to look at the big image and figure out what color to make each of the pixels in
the 100 x 100 pixel layer. That takes a lot of processing.
</font></span></div>
<div><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div><span><font color="#0000ff" face="Arial" size="2">Instead, you can pre-build overviews, either inside or outside of the
image file for your data layer. That way, when you request a map image
like above, MapServer (or OGR) can decide to just use the pre-built
overview. </font></span></div></div><div><span class="sg">
<div><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div><span><font color="#0000ff" face="Arial" size="2">David.</font></span></div></span></div><div><span class="e" id="q_10d0cdefb18725ed_2">
<blockquote style="margin-right: 0px;">
<div></div>
<div dir="ltr" align="left" lang="en-us"><font face="Tahoma" size="2">-----Original Message-----<br><b>From:</b> UMN MapServer
Users List [mailto:<a href="mailto:MAPSERVER-USERS@LISTS.UMN.EDU" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">MAPSERVER-USERS@LISTS.UMN.EDU</a>] <b>On Behalf Of </b>Bruno
Patini Furtado<br><b>Sent:</b> Monday, August 14, 2006 7:50 AM<br><b>To:</b>
<a href="mailto:MAPSERVER-USERS@LISTS.UMN.EDU" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">MAPSERVER-USERS@LISTS.UMN.EDU</a><br><b>Subject:</b> Re: [UMN_MAPSERVER-USERS]
Detail displey when zoom in<br><br></font></div>One thing that might help is
knowing that the MapServer terminology for zoom is Overviews as can be seen in
<a href="http://mapserver.gis.umn.edu/docs/howto/raster_data/#building-internal-overviews" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://mapserver.gis.umn.edu/docs/howto/raster_data/#building-internal-overviews
</a>.<br><br>Also, the GDAL uses the same term in <a href="http://www.gdal.org/gdaladdo.html" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://www.gdal.org/gdaladdo.html</a>
where:<br>
<div style="margin-left: 40px;"><span style="font-style: italic;">The gdaladdo
utility can be used to build or rebuild overview images for most supported
file formats with one over several downsampling
algorithms.</span><br></div><br>
<div><span class="gmail_quote">On 8/13/06, <b class="gmail_sendername">Hooi</b>
<<a href="mailto:wchoonhooi@gmail.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">wchoonhooi@gmail.com</a>>
wrote:</span>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div>I intend to do something like Google Local where when user zoom in, he
can see same area but more details. How can I achieve this in
Mapserver?<br></div></blockquote></div><br><br clear="all"><br>-- <br>"Minds are
like parachutes, they work best when open."<br><br>Bruno Patini
Furtado<br>Software Developer<br>webpage: <a href="http://bpfurtado.net" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://bpfurtado.net </a><br>software development
blog: <a href="http://bpfurtado.livejournal.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://bpfurtado.livejournal.com</a>
</blockquote></span></div><div></div>
</div></blockquote></div><br><br clear="all"><br>-- <br>"Minds are like parachutes, they work best when open."<br><br>Bruno Patini Furtado<br>Software Developer<br>webpage: <a href="http://bpfurtado.net">http://bpfurtado.net
</a><br>software development blog: <a href="http://bpfurtado.livejournal.com">http://bpfurtado.livejournal.com</a>