[mapserver-users] Feature select performance

[Chris Jackson]

Steve

I was pursuing the performance issue on the pmapper mailing list too.  It
transpires it is related to browser performance (from a JS aspect) for the
web apps query/redraw processes -> IE7 - awful (>8mins), IE8 and FF pretty
good - around 20secs for returning/highlighting 5000 features (and building
results table) and Chrome about 13 secs, that is without even creating a
spatial index.  Thanks for the info and I think I may even not have to go
down the db route (which keeps life simple!) just advise IE6/7 users to
switch browsers (not the first webGIS app I know that does this....!)

Thanks
Chris.

On 25 August 2010 18:08, Lime, Steve D (DNR) <Steve.Lime at state.mn.us> wrote:

>  Like with everything it depends…  Selection of features via a bounding
> box shouldn’t be much, or really any, slower than drawing since it’s
> basically the same mechanism for both. Attribute queries can be quite slow
> with shapefiles since MapServer doesn’t do any attribute indexing. That’s
> where the RDMS really adds value. There shouldn’t be much of a difference
> with a bbox query, and in fact, a local shapefile will probably be faster,
> even on larger datasets as long as you’ve build an spatial index file.
>
>
>
> Anyway, it’s what you do with results afterwards that matters and that’s
> probably specific to your application.  I’ve used query files to persist
> selected features over many map draws successfully on modest (50,000
> feature) sized shapefiles.
>
>
>
> Steve
>
>
>
> *From:* Chris Jackson [mailto:webturtles at gmail.com]
> *Sent:* Tuesday, August 24, 2010 10:34 AM
> *To:* Lime, Steve D (DNR)
> *Cc:* mapserver-users at lists.osgeo.org
> *Subject:* Re: [mapserver-users] Feature select performance
>
>
>
> Steve
>
> The selection of layer data is done by a bounding box, though querying by
> parameter values is just as slow.  The mapfile is directly calling up the
> shapefile (I had just followed the P.Mapper examples of displaying/querying
> shapefiles directly).  So probably the answers to those questions lie under
> the hood of P.Mapper, which I assume is using the PHP mapscript.dll to do
> the work.  Is the direct query to shapefile approach v.efficient for larger
> datasets..?.  Ignoring the app I am using what is a good approach to large
> feature datasets from a MapServer perspective?
>
> Thanks
> Chris
>
>
>  On 24 August 2010 14:27, Lime, Steve D (DNR) <Steve.Lime at state.mn.us>
> wrote:
>
> How is the selection done? How is the highlighting done? Those processes
> will really impact performance depending on how things are implemented.
>
> Steve
>
> ________________________________________
> From: mapserver-users-bounces at lists.osgeo.org [
> mapserver-users-bounces at lists.osgeo.org] On Behalf Of Chris Jackson [
> webturtles at gmail.com]
> Sent: Tuesday, August 24, 2010 3:19 AM
> To: mapserver-users at lists.osgeo.org
> Subject: [mapserver-users] Feature select performance
>
>
> Hi all
>
> I have rigged up a webGIS app (P.Mapper framework) where one of the
> underlying datasets is a model grid (many thousand cells) in a shapefile.
>  The data displays nice and quick when just viewing, but if I allow the user
> to select say 5000 cells it is very (extremely) slow to redraw with the
> highlighted cells.  Doing the same task in a very old ArcGIS server web app
> was much quicker (admittedly the data was in SDE/MS SQL).  So my question is
> what is the best way to improve performance - would just transferring the
> shapefile to to say a MS SQL 2005 db with the MSSQLSPATIAL add-on be a good
> step or is there are better way to present the data in the Map file?
> Many thanks
> Chris
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/mapserver-users/attachments/20100825/7d260774/attachment.html