[mkgmap-dev] precompiled sea

Thu Jan 30 11:35:05 GMT 2020

Hi

Having just generated full britain-and-ireland with current trunk
(r4432), I'm also now seeing some tiles (5 out of 101) with sea/land
flipped when using option:
  --generate-sea="multipolygon,extend-sea-sectors,close-gaps=350"
but when I process some of the same tiles with r4295 they are OK.

It's not a problem for me at the moment, I've simply replaced above
with
  --precomp-sea=sea-latest.zip

However I prefer to use --generate-sea for various reasons:
- saves downloading sea.zip every now and again.
- island cut-outs match land features exactly, whereas there were
slight differences with sea.zip.
- not had these problems before.
- no noticeable performance problems.

Sometime I'll try and pin down when the change happened. I hadn't
noticed before because the tiles in the small map I use day-to-day
don't show the problem.

Ticker

On Wed, 2020-01-29 at 22:50 +0000, Mike Baggaley wrote:
> Hi Gerd, up to now I have built my UK map with the sea and land in a
> single
> pass using --generate-sea. However, some tiles are getting the sea
> and land
> inverted, typically where a very small amount of sea is in the tile.
> I was
> trying to see whether if I precompiled the sea, the problem would go
> away -
> I was assuming the tiles of precompiled sea would be bigger because
> they
> contained no other data, so the probability of inversion would be
> reduced. I
> was therefore first trying to generate precompiled sea, then use it
> to build
> my UK map. It may be that my assumption is incorrect and that it
> won't make
> any difference anyway.
> 
> Regards,
> Mike
> 
> -----Original Message-----
> From: Gerd Petermann [mailto:gpetermann_muenchen at hotmail.com] 
> Sent: 29 January 2020 19:22
> To: Development list for mkgmap <mkgmap-dev at lists.mkgmap.org.uk>
> Subject: Re: [mkgmap-dev] precompiled sea
> 
> Hi Mike,
> 
> not sure what you are trying to do. What do you expect to get with
> the last
> command?
> 
> Gerd
> 
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> von Mike
> Baggaley <mike at tvage.co.uk>
> Gesendet: Mittwoch, 29. Januar 2020 19:20
> An: 'Development list for mkgmap'
> Betreff: [mkgmap-dev] precompiled sea
> 
> Hi, I have not used precomp sea before and am struggling to compile
> the sea
> tiles. Using the following process I get a map with no sea:
> 
> Used osmfilter to extract just the coastline data
> Used splitter on the coastline data
> Used mkgmap on the splitter data with a simple style that just
> processes
> coastline and with --generate-sea=multipolygon. I can see some img
> files
> created in my sea folder
> Used splitter again on the original data
> Used mkgmap again with --precomp-sea and --generate-sea=multipolygon
> 
> Am I doing something wrong?
> 
> Regards,
> Mike
> 
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> 
> 
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