<div>Hi Dylan,</div>
<div> </div>
<div>I do something like what you are asking, with CGI mapserver, it may not be right for your needs and may not be the best way, but it may give you some ideas.</div>
<div> </div>
<div>You could have a pull down box of the polygon types on your website, some javascript passes the selected value from the box to a variable in a hidden input in your html form. Make the default value a value that it does not occur in your dataset.
</div>
<div> </div>
<div>In your mapfile, have an extra layer for that data under the primary layer (so that it is drawn on top of the primary layer on the map), with a filter item whose value is the variable in your form input ... FILTER %polytype% or whatever. With a class that will show your selected polygons highlights however you want.
</div>
<div> </div>
<div>You may need to set the hidden input value in your HTML form to your variable to keep your selection highlighted as you pan/zoom: </div>
<div> </div>
<div><input type='hidden' name='polytype' value='[polytype]'> </div>
<div> </div>
<div>and if you have an entry page to your website that sets up the initial map parameters, you should assign the default value there:</div>
<div> </div>
<div><input type='hidden' name='polytype' value='XXXX'> </div>
<div> </div>
<div>In our case, we are using a Flash interface to keep track of everything, so the 'instancing' isn't a problem, and the variable goes into a WHERE clause in an SQL query in our layer's DATA parameter, accessing the spatial data from PostGIS.
</div>
<div> </div>
<div>Cheers,<br>Ken Lord</div>
<div>Vancouver BC</div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> <br><br> </div>
<div><span class="gmail_quote">On 7/22/05, <b class="gmail_sendername">Dylan Beaudette</b> <<a href="mailto:dylan@iici.no-ip.org">dylan@iici.no-ip.org</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Greetings,<br><br>just wondering if it is possible to highlight all matching occurrences of a<br>given polygon type after a user has queried a single polygon.
<br><br>for example, there are 5 polygons on the screen, the user clicks on poylgon<br>type 1. A querymap image is returned with polygon 1 highlighted. Would it be<br>possible for a similar operation to highlight all polygons of type 1 in the
<br>returned querymap image? ... or would this require mapscript... ?<br><br><br>thanks in advance!<br><br>--<br>Dylan Beaudette<br>Soils and Biogeochemistry Graduate Group<br>University of California at Davis<br>530.754.7341
<br></blockquote></div>