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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Actually I’m warming to the idea first presented in the RFC, basically a cluster driver. It concentrates all this processing in one spot and doesn’t further complicate things like msDrawLayer()… I don’t know a way to really address querying without going this route. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Steve <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Tamas Szekeres [mailto:szekerest@gmail.com] <br><b>Sent:</b> Wednesday, February 16, 2011 6:27 AM<br><b>To:</b> Lime, Steve D (DNR)<br><b>Cc:</b> mapserver-dev@lists.osgeo.org<br><b>Subject:</b> Re: [mapserver-dev] MS RFC 68: Support for combining features from multiple layers (Call for discussion)<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>Steve,<br><br>As far as I can see, your preference is to implement the clustering within the same layer instead of referring to another layer, right?<br>(With regards to the parameters there's not too much difference in the concept with having processing options vs. built in parameters.)<br><br>With this end in view, I foresee 2 main problems which is not quite trivial in this approach.<br><br>1. How the FeatureCount parameter will be used for labelling the clustered features?<br>2. How can we make the clustered features selectable (queryable). / this is not a strong requirement of mine at this phase /<br><br><br>With regards to the implementation how about invoking a custom LayerOpen in msDrawVectorLayer, something like?:<br><br>if (needtocluster) // based of the existence of the cluster parameters<br> msClusterLayerOpen(layer); // this would override the vtable methods: LayerGetItems/LayerInitIteminfo/LayerWhichShapes/LayerNextShape<br>else<br> mslayerOpen(layer);<br><br>// the remaining code would be the same in effect (not modified)<br><br>msLayerWhichItems(layer); // LayerGetItems/LayerInitIteminfo would be aware of the FeatureCount parameter.<br>msLayerWhichShapes(layer, rect) // build up the cluster database here, call WhichItems/LayerWhichShapes/LayerNextShape for the underlying connection type<br>while(msLayerNextShape(layer, shape) == MS_SUCCESS) // shapes would be served from the cluster database<br>{<br> msDrawShape(shape); // normal drawing process <br>}<br>msLayerClose(layer); // restore the original vtable<br><br><br><br>Best regards,<br><br>Tamas<br><br><br><br><o:p></o:p></p><div><p class=MsoNormal>2011/2/15 Lime, Steve D (DNR) <<a href="mailto:Steve.Lime@state.mn.us" target="_blank">Steve.Lime@state.mn.us</a>><o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>Sorry, I mean clustering shouldn’t be a new connection type, rather a block or optionally a set of processing directives, so:</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>LAYER</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> NAME mypoints</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> TYPE POINT</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> # whatever data and/or connection params</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> CLUSTERS # or processing directives</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> END</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> # class and style info</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>END</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>The decision to use a block or processing directives would depend on the complexity of configuration. If clustering could</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>potentially support lots of tuning then I’d favor an explicit configuration block.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>I think both pieces of functionality outlined are potentially useful. I’d recommend limiting the scope of the RFC to clustering </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>to start with… There is some limited (and non-configurable) support for not labeling over point features already present in</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>the label cache code so I see more limited utility in the layer combination portion of the RFC.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>Steve</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><div style='border:none;border-top:solid windowtext 1.0pt;padding:3.0pt 0in 0in 0in;border-color:-moz-use-text-color -moz-use-text-color'><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span style='font-size:10.0pt'>From:</span></b><span style='font-size:10.0pt'> <a href="mailto:mapserver-dev-bounces@lists.osgeo.org" target="_blank">mapserver-dev-bounces@lists.osgeo.org</a> [mailto:<a href="mailto:mapserver-dev-bounces@lists.osgeo.org" target="_blank">mapserver-dev-bounces@lists.osgeo.org</a>] <b>On Behalf Of </b>Tamas Szekeres<br><b>Sent:</b> Tuesday, February 15, 2011 11:38 AM<br><b>To:</b> Lime, Steve D (DNR)<br><b>Cc:</b> <a href="mailto:mapserver-dev@lists.osgeo.org" target="_blank">mapserver-dev@lists.osgeo.org</a><br><b>Subject:</b> Re: [mapserver-dev] MS RFC 68: Support for combining features from multiple layers (Call for discussion)</span><o:p></o:p></p></div><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'> <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>2011/2/15 Lime, Steve D (DNR) <<a href="mailto:Steve.Lime@state.mn.us" target="_blank">Steve.Lime@state.mn.us</a>><o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>I see value in both but kinda think they should be handled with separate RFCs since you don’t need one for the</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>other and neither problem is trivial.</span><o:p></o:p></p></div></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><br>Steve,<br><br>I can accept to create separate RFCs (however I require them both in my project to succeed ;-)<o:p></o:p></p></div><blockquote style='border:none;border-left:solid windowtext 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt;border-color:-moz-use-text-color -moz-use-text-color -moz-use-text-color rgb(204, 204, 204)'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>At least on the clustering side I don’t think that should be handled as a connection type. Rather I’d favor a new</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>CLUSTER block where you’d set the various tolerance and scale values. That way you could add clustering to a</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'>point layer without much effort. I think it needs to be that simple.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p></div></div></blockquote><div><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><br>I don't see the difference with regards to the data processing. For the setting of the parameters via a CLUSTER block instead of some PROCESSING option doesn't seem to differ significantly. But if you want to include this algorithm somewhere into the MapServer core that would be another case.<br><br>Best regards,<br><br>Tamas<o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div></div></div></div></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>