Hi all, Attached is 2nd version of the patch.
The improvements are a bit better, although I've removed one change in PolygonSplitterBase which reduces the number of splits in rare cases (e.g. when the map contains large sea areas). I think this change is okay, but it is not related to the LinePreparer and thus should be handled separately. A new binary containing the attached patch(es) is here: http://files.mkgmap.org.uk/download/302/mkgmap.jar If I here no complains I'll commit both patch next wednesday. Gerd ________________________________ Von: mkgmap-dev <[email protected]> im Auftrag von Alexandre Loss <[email protected]> Gesendet: Samstag, 16. Juli 2016 19:43:23 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] [Patch v1] improve LinePreparer to reduce img size Great discovery Gerd! Enviado do meu iPhone Em 16 de jul de 2016, ?s 14:28, Gerd Petermann <[email protected]<mailto:[email protected]>> escreveu: Hi all, during the last days I tried to find more about the way how mkgmap stores polygons, esp. why we have some limits. While doing that I stumbled over an old comment in LinePreparer.java: // I don't care about getting the smallest possible file size so // err on the side of caution. which made me curious because I do care ;-) I found out that Garmin offers a "trick" in the delta encoding which allows to reduce the needed bytes in some cases, the imgformat-1.0.pdf explains this in detail, search for " only the sign bit is set ". This "trick" helps esp. well when coastline polygons or rivers are stored. I can explain this more detailed if somebody likes to know more, for now I'd like to hear if the trick causes any problems, I did not find any so far. A binary with this and a slightly improved overview_levels_v2.patch can be found here: http://files.mkgmap.org.uk/download/301/mkgmap.jar Depending on the data a single tile with size ~5MB may be reduced by 50 - 500+kB. Gerd <reduceImgSize_v1.patch> _______________________________________________ mkgmap-dev mailing list [email protected]<mailto:[email protected]> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
reduceImgSize_v2.patch
Description: reduceImgSize_v2.patch
overview_levels_v3.patch
Description: overview_levels_v3.patch
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