Hi Gerd,
Nested polygons may not be as rare as you think, it was a situation I was
thinking about when this discussion started. Zambia has a number of large
wetlands where there are islands with wetland within the island, particularly
as these wetlands are seasonal and the islands will be inundated during the
rains with the low points of the island staying wet once the water recedes.
This is similar to your forest with a lake that contains a forest.
Dave
Original Message
From: [email protected]
Sent: 18 March 2021 12:21
To: [email protected]
Reply to: [email protected]
Subject: Re: [mkgmap-dev] tile takes very long time to generate
Hi all,
I still struggle with the unit test because it's hard to say what we want to
get in special cases.
The current code doesn't really work in the way that I expected. I always
thought that roles like "inner" and "outer" are completely ignored and that
mkgmap calculates and uses the correct roles. This is only partly true. See
attached file with MP were a forest contains a lake that contains a forest.
For a nested polygon where the innermost ring has wrong role "inner" this
doesn't work as expected. The forest in the lake is ignored. With the correct
role "outer" it is not ignored. No idea if this is intended or an error.
Fortunately nested MP are very rare.
Gerd
________________________________________
Von: mkgmap-dev <[email protected]> im Auftrag von Ticker
Berkin <[email protected]>
Gesendet: Montag, 15. März 2021 17:15
An: Development list for mkgmap
Betreff: Re: [mkgmap-dev] tile takes very long time to generate
Hi Gerd
You might consider the some of the ideas here as improvements to the
initial parts of MP processing.
This is a patch based on trunk rather than the new branch. It isn't
structured as for final usage, rather for minimising the spread of
changes, working in parallel with the existing code so I could see if
found the same MP problems as the existing code and having clearly
identifiable diagnostics in the log file.
Ticker
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