[mkgmap-dev] [PATCH V1] Idea for minor speed improvement for boundary preprocessingFrom GerdP gpetermann_muenchen at hotmail.com on Fri Mar 2 16:18:45 GMT 2012
Hi WanMil, yes, your solution is better. I wanted to do it in the same way, but failed to find the correct tile sizes for areas that cover e.g. 7 split rectangles (the middle is not on the grid) two small points: 1) the variable names midLon and midLat are a bit missleading, since you don't split in the middle, but near the middle (which perfectly solves my problem described above) 2) You removed my added try/catch from BoundaryPreparer.run() I hope you found a better solution? I needed it there to make assert work in e.g. splitArea() Gerd WanMil wrote > > Hi Gerd, > > that's great! > >> Hi WanMil, >> >> this was a very good hint :-) >> >> Time for african boundaries was 250 secs with /branch/performance/r2225, >> 267 >> secs with trunk, >> and with this patch it is now 152 secs > > wow, that's more improvement than I expected. > >> >> - use simple quadtree in BoundarySaver.splitArea() > > You are a quadtree guy. > In this case I thinks it's more irritating and complex to split the area > into four subareas. I've changed that to split into two subareas and the > code is now much easier to read (I think so..?!?) and performs in > similar speed. > > WanMil > >> - add try/catch in BoundaryPreparer.run() to allow e.g. usage of assert. >> Without that, >> an assertion was handled by the threading routines and caused program >> stop >> without any >> message. >> >> Please double check this, I am still not so experienced >> with try+catch and wrong placed >> >> Ciao, >> Gerd >> >> http://gis.19327.n5.nabble.com/file/n5512906/splitArea_v1.patch >> splitArea_v1.patch >> >> >> WanMil wrote >>> >>> Hi Gerd, >>> >>> boundary preprocessing takes quite a lot of time. That's not a big >>> problem because it's performed only by some people who publish their >>> results. >>> >>> But I think some speed improvements would not be bad anyhow?! >>> >>> While preprocessing asia and america I go an idea. The area of a >>> boundary is splitted into the raster. But each time the complete area is >>> intersected to the raster. In case an area is big and/or complex >>> (boundary of russia, USA, canada etc.) this takes a long time. It would >>> be possible first to cut the area into smaller pieces (columns or rows >>> of the raster) and then do the final cut to the raster. Maybe this saves >>> time because the column or row areas should be less complex. >>> >>> What do you think? >>> >>> WanMil >>> _______________________________________________ >>> mkgmap-dev mailing list >>> mkgmap-dev at .org >>> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev >>> >> >> >> -- >> View this message in context: >> http://gis.19327.n5.nabble.com/PATCH-V1-Idea-for-minor-speed-improvement-for-boundary-preprocessing-tp5512906p5512906.html >> Sent from the Mkgmap Development mailing list archive at Nabble.com. >> _______________________________________________ >> mkgmap-dev mailing list >> mkgmap-dev at .org >> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev at .org > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > -- View this message in context: http://gis.19327.n5.nabble.com/PATCH-V1-Idea-for-minor-speed-improvement-for-boundary-preprocessing-tp5512906p5531433.html Sent from the Mkgmap Development mailing list archive at Nabble.com.
- Previous message: [mkgmap-dev] [PATCH V1] Idea for minor speed improvement for boundary preprocessing
- Next message: [mkgmap-dev] [PATCH V1] Idea for minor speed improvement for boundary preprocessing
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
More information about the mkgmap-dev mailing list