[Xastir] Rtree

[Tom Tessier]

I agree with Curt. I'm using maps covering whole provinces. They take about
20 seconds to load, but pans are 2 seconds or so each. Works great for that.

-Tom
> On Sat, 26 Mar 2005, James Ewen wrote:
>
> > I finally got around to trying out the rtree option.
> >
> > It's not on my list of favourites... I find that it slows down the
display
> > dramatically. Once you've zoomed in and out quite a bit, things speed up
a
> > little. However, those first couple times take 15-20 times longer to
display
> > than without rtree. The speed increase once rtree is in place, doesn't
make
> > much difference for me. It seems that the rtree data clears out of
memory
> > quite quickly as well.
> >
> > It could quite possibly be the way I have my shapefile data split up. I
cut
> > the province up into Maidenhead grid squares, and also pulled the major
> > highways out for the whole province.
>
> I think your last comments there are the key.  Rtree appears to work
> best for me when I'm using larger shapefiles or zooming in quite a
> ways into a shapefile.  It helps in quickly finding the shapes in
> the file that fit your view.
>
> If you have smaller shapefiles, Xastir's native code that checks
> whether the bounding rectangle fits within your view will knock any
> that don't fit out of the loading procedure.  Therefore rtree
> doesn't get a chance to do its thing.
>
> Rtree does have to create the tree the first time the file is
> loaded, so that first load takes longer.  More memory with largish
> shapefiles for you zoom levels of interest mean that rtree really
> shines.  The converse is that will less memory or smaller shapefiles
> rtree isn't the option for you.
>
> -- 
> Curt, WE7U. archer at eskimo dot com
> http://www.eskimo.com/~archer
>   Lotto:  A tax on people who are bad at math. - unknown
> Windows:  Microsoft's tax on computer illiterates. - WE7U.
> The world DOES revolve around me:  I picked the coordinate system!"
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