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[mkgmap-dev] [Patch] Faster BoundaryGrid

From GerdP gpetermann_muenchen at hotmail.com on Thu May 3 07:58:20 BST 2012

Hi WanMil,

you are right, the patched code is a bit slower for the normal case.
I see two solutions:
1) We don't allow directories in the zip file. With this restriction we can
simply stop searching if the wanted bnd file is not found instead of
traveling through thousends of entries.
We can alarm the user when we find a directory structure within the zip.
2) We save the list that is created in LocationHook.init() and use it as a
parm for the BoundaryGrid

I'd prefer option 1, what do you think?


GerdP wrote
> Hi WanMil,
> attached is a small patch which drastically improves BoundaryGrid for 
> tiles that contain mostly sea. I found such a tile in south-america, and
> the patched version is > 10 times faster. 
> It contais a large part of the pacific, and BoudaryGrid searches the
> boundary zip file for 
>> 5000 different *.bnd files, most of them do not exist in your
>> bounds_20120401.zip , so the 
> code in BoundaryUtil searches through all elements of the zip file to find
> out that it doesn't exist.
> The patch creates a HashSet first with the  available files and calls the
> load routine only for 
> those that exist.
> Gerd
>  http://gis.19327.n5.nabble.com/file/n5680180/BoundaryGrid.java.patch
> BoundaryGrid.java.patch 

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