[Qgis-developer] Quantum GIS and fileservers performance with shape files

[Tim Sutton]

Hi

On Mon, Mar 14, 2011 at 3:21 PM, Windmuller, H (Hans)
<Hans.Windmuller at pwn.nl> wrote:
> LS,
>
> We are using Quantum GIS for our wardens. I have a question of which I don't know where I can put it so I'm hoping one of you can get me into the right direction.
>
> On our clients we have Windows XP sp2 as Operating System and on our fileservers we have Microsoft Server 2003 as Operating System.
> We store our data files (shape files and raster files (ecw)) on the central file server.
> For a shape file with a .shp file (size 3 MB) and a .dbf file (size 155 MB) it takes 7 minutes and 30 seconds to get the shape displayed on screen. Between the two locations there is a WAN of 10 Mbps.
>
> Other applications (MapWindow, ArcGIS, DIVA-GIS) only take 40 seconds to do the same.
> My presumption is that Quantum GIS first downloads the entire shape file onto the client before rendering. The other applications seem only to download the .shp file and to approach the .dbf file on the file server.
>
> I have observed that it is the .dbf file that is taking the time because when I deleted a number of fields in the specific .dbf file time dropped to about 3 minutes (and the size of the .dbf file dropped to 85 MB).
> The other applications still gave the same result of 40 seconds.
>
> Can someone of you please tell me how Quantum GIS handles shape files on a remote file server and if / when Quantum GIS will be able to get the same results in performance as the other applications mentioned above?
>
> I'm looking forward to receiving your answer.
>
>

Since we are using gdal/ogr for reading shapefiles, this is probably a
question better asked on the gdal mailing list. Let us know if you get
some interesting response from them!

By the way for such a client / server environment, it is *much* better
performance wise and logistically to put your data into PostGIS.

Regards

Tim


> Kind regards
> Met vriendelijke groet,
>
> Hans Windmüller
> medewerker GIS
> Rijksweg 501
> 1991 AS  VELSERBROEK
> 0251-661035
> 06-53792012
> hans.windmuller at pwn.nl
> www.pwn.nl
>




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