[GRASSLIST:10787] Re: How can I reduce the loading time of GRASS-layers in UMN Mapserver

[Radim Blazek]

GRASS does not save spatial index in file becouse it
occupied too much space and spatial index is used only occasionly.
So spatial index could make it slower but 6 times seems too much.

My guess is that it is caused by attributes. Try to go to the
vector directory in GRASS and rename temporarily 'dbln' file.

Also for testing to avoid the difference between nature
of topological and SF format try to test with points or lines.

Radim


On 3/6/06, Wolfgang Qual <Wolfgang.Qual at gmx.net> wrote:
> Dear list,
> I created a mapfile for two identical themes: One of them is a shapfile, the
> other one is a grass vector dataset. The shapefile contains a *.qix-file
> which was created using the program shptree.
> I compared the loading time for the two themes using the command "time wget
> -O /dev/null "http://path/to/the.map". Result: the grass theme took about 12
> seconds (on a local machine), shapefile only 2s.
> My Question therefore: is there a possibility to speed up grass layers in
> the mapserver application (something like shptree does?)? The attribute
> table of the grass-theme is a (default) dbf-file.
>
> Declaration of the grass-layer in the mapfile:
>
> # OGR-Layer aus GRASS
> #_# START LAYER l8
> LAYER  NAME "l8"
> TYPE polygon
> STATUS ON
>     CONNECTIONTYPE OGR
>     CONNECTION
> "/home/wqual/grassdata/muenchen/stadtbezirk/vector/block/head"
>     DATA "1"
>     METADATA
>       LTITLE "l8"
>     END #metadata
> ### TYPE Polygon -- LEGTYPE 0x01 -- SYMTYPE 0x02
> ### singlepolyleg
>    CLASSITEM "cat"
>    CLASS NAME "Block_GRASS"
>     COLOR 255 0 0
>     OUTLINECOLOR 20 200 10
>    END #CLASS
> #_# LAYER l8 QUERY
> END # LAYER l8
>
> I would be very happy to receive some hints/tips on this issue.
>
> Best regards,
>
> Wolfgang
>
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