I’ve got a large Spatialite database with a table of lines (roads, rail and water). I created a spatial index of the geometry to speed things up.
This works amazingly well when I’m zoomed in close. However, when I’m zoomed out in QGIS 1.8, the display is slower than I’d hope. And so I created a separate Table-View of just the major roads, intending to speed things up. That didn’t work—I suppose because the display is still plowing through all the roads just to find the major roads.
Is it justified for me to create another spatial table of “just the major roads” to use when I’m zoomed out. Or, is there some way to index the queried column for major roads, or some other trick, and thus create a very speedy display of the major roads without creating a brand new spatial table? I’m trying to keep my Spatialite database as small and practical as possible, without filling it with a lot of redundant tables of data. I’m finding that Spatialite is extremely quick, but perhaps I’m expecting too much performance, though I’d still like to get as much as possible.