<br><br><div class="gmail_quote">2009/10/9 Martin Kofahl <span dir="ltr"><<a href="mailto:M.Kofahl@gmx.net">M.Kofahl@gmx.net</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Tamas,<br>
this is a very interesting rfc. I'm still reading through your patches in order to follow the examples as I haven't heard of vtables yet. Can you please clarify some things for me?<br>
<br>
- Any filterings are probably done in mapfilter.c, currently for MS_SHAPE_POINT/LINE/POLYGON. Does this has to be extended for all other types including raster?<br>
<br></blockquote><div><br>Martin,<br><br>The concept of RFC22 (<a href="http://mapserver.org/development/rfc/ms-rfc-22a.html">http://mapserver.org/development/rfc/ms-rfc-22a.html</a>) is related only to the 'data source' vtable, and we could only filter vector data (ie. shapes) by using this approach. With regards to the raster data this could provide an option only to filter the tiles by the tile indexes (when using tiled rasters).<br>
<br>If you're about to exclude arbitrary regions then you should probably plug in to the renderer vtable (rendererVTable) which is a pretty new concept in MapServer. I could imagine an intermediary renderer which would be capable to modify the image rendered by another renderer. However this option is not covered by RFC22 at all.<br>
<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
- There's a mail on the list saying that performance is quite slow. Have you done any measurements?<br>
<br></blockquote><div><br>I'm not aware of much issues with the performance of this concept itself. I guess you're pointing to the performance issue of the 2-phase query behaviour of MapServer which would be one of the issues addressed by RFC22. I must mention that this problem has already been addressed by MapServer in another way (see: <a href="http://mapserver.org/development/rfc/ms-rfc-52.html">http://mapserver.org/development/rfc/ms-rfc-52.html</a>)<br>
<br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
- There's no vote on this rfc. Does it make sense to work on it, so how are the chances that your concept will go into the development version.<br>
<br></blockquote><div><br>Every significant change would normally require an RFC and should be approved by the MapServer PSC in a voting process. I would normally prefer to issue a vote if I had at least some of the PSC members support the concept, but it seems this one has lack of this support due to the presumed complexity of these additions, which would be considered to violate the designated objective of "MapServer is not a
full-featured GIS system, nor does it aspire to be." (<a href="http://mapserver.org/">http://mapserver.org/</a>)<br><br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
- Can you give an abstract of work which is to be done?<br>
<br></blockquote><div><br>I think we should normally require:<br><br>1. An RFC to describe the required changes to satisfy with your needs to be able to discuss on<br>2. The RFC should be negotiated on the mapserver-dev list<br>
3. Issue a vote on the RFC<br>4. If the voting is passed then implement the changes and modify the doc accordingly <br></div></div><br><br>I currently don't have enough motivation to proceed with this RFC, as currently I have no such requirements in my project actually. However I would still support having such feature in MapServer (it should probably be extended to the renderer vtables as well) if someone would feel enough power to do some polishing on that.<br>
<br><br>Best regards,<br><br>Tamas<br><br><br><br>