<span class="gmail_quote"></span>I am not sure of any mapscript approaches for this type of problem. I currently do this to create a grid that shows how many flights cross a given grid cell in my application at <a href="http://maps.macnoise.com/interactive/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://maps.macnoise.com/interactive/</a> (select flight tracks grid from the layer list) using postgis.<br><br>The general approach that I have is to either use a pre-built grid or a plpgsql function that builds the grid on the fly and to create a layer in mapserver that does an on the fly intersection between the two with a data statement similar to this:
<br><br>DATA "the_geom from (select count(<a href="http://f.id" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">f.id</a>) as count, g.geom as the_geom from grid as g,flighttracks as f where g.geom
&& f.geom and crosses(g.geom,f.geom)) using unique the_geom using srid=-1"
<br><br>David<div><span class="e" id="q_1105f09e54f0247d_1"><br><br><br><br><div><span class="gmail_quote">On 1/26/07, <b class="gmail_sendername">Rodrigo Del C. Andrade</b> <<a href="mailto:rodrigo.andrade@digitro.com.br" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
rodrigo.andrade@digitro.com.br</a>> wrote:
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<br>
Hi dear list.<br>
<br>
I am trying to implement in java mapscript an application that
draws on-the-fly contours around areas with a high ocurrence rate of a
given event, something like the topics discussed in here:
<a href="http://article.gmane.org/gmane.comp.gis.mapserver.user/17924" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://article.gmane.org/gmane.comp.gis.mapserver.user/17924</a>. <br>
I understand it is not easy, so I am taking my steps one at a time.
Being quite new to GIS programming, I am going trough the usual misteps.<br>
<br>
My first problem is actually dividing the area into subzones where
I can count the ocurrences of said events inside each rectangle to feed
the statistic analysis. I have tried using a graticule item on a line
layer, but I cant seem to find a query method that will give me
something I can work with (boundaries, polygons, the works), even
though the grid has been drawn quite nicelly. <br>
I understand I probably missed completelly the point of a GRID
object inside a LINE type layer, but is there some built in way (trough
grid or any other method) to chop a layer in equal rectangles so I can
iterate trough each of them checking for ocorrences? <br>
<br>
Thanks a lot.<br>
<br>
<div>-- <br>
<font color="#000000" face="Verdana, Arial, Helvetica" size="1">
<br>
<br>
<font color="#000000" size="2"><b>Rodrigo Del C. Andrade</b></font><br>
<font color="#606060"><i>Estagiário Nível Superior</i></font><br>
<font color="#606060"><i>SIC - SSE - Soluções Segurança Pública</i></font><br>
<br>
<font color="#000080"><b>DÍGITRO TECNOLOGIA</b></font><br>
<font color="#000000"><b>E-mail:</b></font>
<a href="mailto:rodrigo.andrade@digitro.com.br" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)"><font color="#606060">rodrigo.andrade@digitro.com.br</font></a><br>
<font color="#000000"><b>Fone:</b></font>
<font color="#000000">+55 48 3281-7390 / +55 48 3281-7000</font><br>
<font color="#000000"><b>Fax:</b></font>
<font color="#000000">+55 48 3281-7299</font><br>
<font color="#000000"><b>Site:</b></font>
<a href="http://www.digitro.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)"><font color="#606060">www.digitro.com</font></a>
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</blockquote></div><br><br clear="all"><br></span></div>-- <br>************************************<br><span class="sg">David William Bitner
</span><br clear="all"><br>-- <br>************************************<br>David William Bitner