[Qgis-user] Reqgis 0.10 slow digitizing with grass

[Maciej Sieczka]

maning sambale pisze:
> Hi,
> 
> I am using qgis for editing attributes of a grass vector.  The other 
> layers loaded are 3 GRASS rgb images,

I recommend exporting the "GRASS rgb images" (they are "groups", are
they?) from GRASS into GeoTIFF with r.out.gdal.sh (if you go for the C
r.out.gdal counterpart, make sure you run gdal_translate on the output
to reduce the file size; somehow the C r.out.gdal produces GeoTIFFs
bigger than gdal_translate can). Build overviews for your GeoTIFFs with
gdaladdo then (I'd go external overviews - make the GeoTIFF read only
and then run the gdaladdo on it to achieve this). Overviews should speed
up their render times much.

> a shapefile.

I'm not sure, but maybe building an index in QGIS can help, ?. And it
would not harm to process the shapefile with ogr2ogr without parameters
which might reduce it's size - I happened to notice this works with some
Shapefiles I got. At worst, even if the shapefile won't render faster it
will occupy less disk space and might have lower memory footprint.

Maciek

-- 
Maciej Sieczka
www.sieczka.org