[mkgmap-dev] Duplicate cities

Thu May 21 17:31:47 BST 2015

Hi Colin,

what difference do you expect when you 
are able to configure that value?
I'd expect a few MB difference in the OSM file size
and nearly no difference in mkgmap output,
on the other hand it woud be another complicated
option.

Gerd

Date: Thu, 21 May 2015 18:25:12 +0200
From: colin.smale at xs4all.nl
To: mkgmap-dev at lists.mkgmap.org.uk
Subject: Re: [mkgmap-dev] Duplicate cities

Could the admin_levels be made configurable in some way? There are considerable differences in the size of these areas between different countries. I am thinking particularly of the lower admin_level (5) which might be better set to 6 (or even 8) in the UK. Level 5 corresponds to "regions" which are basically only for statistics and some government stuff - not many people would know what region they are in (except they could probably guess because they are called things like "South East England"). Level 6 corresponds to Counties, and everyone uses them.

//colin

On 2015-05-21 17:00, Gerd Petermann wrote:

Hi Andrzej,

I tried using --boundary-tags=administrative        
for splitter, the amount of additional data depends
on the size of the largest boundaries.

Attached is a small patch that changes splitter so
that it keeps administrative boundaries complete
when the admin_level is between 5 and 11 (including).

This doesn't add much data to the output files
in comparison to --boundary-tags=administrative        
when splitting e.g. Brazil with --max-nodes=800000
and --output=o5m:
a) r422 output size: ~ 359 M 
b) patched version : ~381 M 
c) unpatched r422 with  --boundary-tags=administrative: 402 M

I've also tested the effect on mkgmap.
As expected, version a) produces some wrong / duplicate POI,
but I don't see them for b) or c).
The throughput is nearly identical, and the final img size is also almost equal.

So, I think the patch is the best compromise.

Gerd

> Date: Thu, 21 May 2015 12:56:43 +0200
> From: popej at poczta.onet.pl
> To: mkgmap-dev at lists.mkgmap.org.uk
> Subject: Re: [mkgmap-dev] Duplicate cities
> 
> Hi Gerd,
> 
> > Hmm, splitter keeps most mp-relations complete, we only
> > exclude some boundary relations.
> 
> I see. But maybe potential increase wouldn't be that big, if you add 
> boundaries?
> 
> Or maybe you can preserve only some levels of boundaries?
> 
> Or you can use boundary data form --bounds option?
> 
> Anyway, I prefer version 1 - keep complete relation, that could be 
> useful for mkgmap.
> 
> -- 
> Best regards,
> Andrzej
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev

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