On Fri, Mar 09, 2007 at 01:07:36PM -0600, we recorded a bogon-computron collision of the <[EMAIL PROTECTED]> flavor, containing: > I've been thinking about ways to simplify map configuration, and an > idea that just hit me was to combine TIGER shapefiles from multiple > counties to make one huge shapefile, reducing the set to three or > four per state. I know I'm gonna take a hit the first time I read a > big shapefile, but rtree should save me after that first one.
I don't know if you'll really save that much. Having smaller, tiled shapefiles would probably save you more (they could be excluded in toto). There is not a huge cost to searching an rtree, but there is a cost. I'd be interested to see your results. > Can I configure rtree's cache timeout value? Not at the moment. The cache purge frequency is hard coded as the "PURGE_PERIOD" preprocessor macro. There's no reason that couldn't be changed. > I know there's not a > slider on the timer menu and I would probably need to hack the > source. Other than the obvious permanent memory utilization, is > there any reason I shouldn't make rtree's cache live forever? That's the only reason it's not permanent --- my logic was that if an rtree hasn't been used for over an hour, the benefit of having that memory used isn't there --- rtree is a memory/time trade-off, and if you're not zooming in and out or panning a bunch, the memory is lost for no speed gain. If you *are* using it, the rtree isn't purged. Having the cache time out user-configurable makes some sense, though. It's just never really come up as a priority yet. I'm all for it if you wanna hack. The relevant code is in shp_hash.c, all using the macro "PURGE_PERIOD". The function purge_shp_hash() is called (from main.c) very often, but returns doing nothing if the period hasn't passed since the last time it purged. -- Tom Russo KM5VY SAR502 DM64ux http://www.swcp.com/~russo/ Tijeras, NM QRPL#1592 K2#398 SOC#236 AHTB#1 http://kevan.org/brain.cgi?DDTNM "And, isn't sanity really just a one-trick pony anyway? I mean all you get is one trick, rational thinking, but when you're good and crazy, oooh, oooh, oooh, the sky is the limit!" --- The Tick _______________________________________________ Xastir mailing list Xastir@xastir.org http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir
