I am not sure about MySQL, but if you use PostGreSQL and the PostGIS
spatial extension you can query a db table using a spatial bounding box
(e.g. the spatial extents of the tile)
(<a href="http://postgis.refractions.net/docs/ch06.html#id2789996" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://postgis.refractions.net/docs/ch06.html#id2789996</a>). This
provides the points for the area of interest only.<br>
<br>
In fact, you might as well create a PostGIS layer and load it into a
MapServer map file since you have to get the points from a database
anyway. MapServer then does the 'extents' query and adds the points to
the map for you (if I'm not mistaken).<br>
<br>
Aaron<br><br><div><span class="gmail_quote">On 2/28/06, <b class="gmail_sendername">Base Bloc</b> <<a href="mailto:chris@basebloc.com">chris@basebloc.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>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Dear all,</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">First off I would like to say that ka-map 0.2 is a fantastic
piece of kit and thanks for all the work that people have put in to this.</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">I
am currently building an application using 0.2 and I am
using the addObjectGeo function to add markers along with mouseover
events (pop-up
windows) to the map. All is working as it should and is looking good.
My
concern now is the number of markers; the application is covering most
of Southeast Asia and the number of markers is going to be
high. I am looking to use Ajax
to connect to a MySQL database to retrieve the point data relevant to
the area
of the map being viewed, as if all of the points were to be retrieved
in one go
it would result in a serious performance hit for the user.</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">I'm no ka-map expert, but I was wondering how ka-map
does this efficiently with the tiles; as in it gets x number of tiles closest
to the area being viewed then moves outwards, is there anyway to use the
variable(s) that are being sent to the server to request the tiles to also
query the database and return the point data in an equally efficient manor?</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Thanks in advance for your thoughts.</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Chris</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> </span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">~~~~~~~~~~~~~~~~~~~~~~~~~~~</span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">Christopher Brown</span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">Head of Internet Development</span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">Base Bloc Cambodia</span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">#33, 123, Phnom Penh, Cambodia.
</span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">P.O. Box</span></font><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">
2086</span></font><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;"></span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;"><a href="http://www.basebloc.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">www.basebloc.com
</a></span></font></p>
<p><font color="navy" face="Arial" size="1"><span style="font-size: 8pt; font-family: Arial; color: navy;">Tel (+885) 12 315 302</span></font></p>
<p><font face="Times New Roman" size="2"> </font></p>
</div>
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</div><br><br clear="all"><br>-- <br>+--------------------------------------------<br>| Aaron Koning<br>| Information Technologist<br>| Prince George, BC, Canada.<br>+--------------------------------------------<br>|
<a href="http://datashare.gis.unbc.ca/fist/">http://datashare.gis.unbc.ca/fist/</a><br>| <a href="http://datashare.gis.unbc.ca/gctp-js/">http://datashare.gis.unbc.ca/gctp-js/</a><br>+--------------------------------------------