[OSM-talk] Blue sea tiles for tiles at home

[80n]

Frederik
The intention was that if the way had more than 400 segments then Frollo
should leave it alone.  I think it actually tries to sort the first 400
segments and then leaves the rest alone.

A patch is obviously needed....

80n


On 4/24/07, Frederik Ramm <frederik at remote.org> wrote:
>
> Hi,
>
>     I found the problem that created the funny zig-zagged lines - a
> quite spectacular example of which is here in the Outer Hebrides (modern
> art, I say!):
>
>
> http://www.informationfreeway.org/?lat=7892620.5527&lon=-795919.49377&zoom=12&layers=B000
>
> Frollo has a limit of 400 segments per way (it was originally 800, and
> then I reduced a constant somewhere in frollo2.xsl because some
> renderers were complaining they got "possible endless recursion" error
> messages).
>
> Until now I thought that if ways get more complex than that, Frollo
> would just leave the way alone. But it seems that the way gets messed up
> somehow.
>
> Here is a boiled-down example with just the coasline from the Portsmouth
> harbour tile 2036,1374:
>
> http://www.remote.org/frederik/tmp/broken-area-with-frollo.osm
>
> It is the result coming out of close-areas.pl, with one coastline way of
> about 600 segments. It renders fine with osmarender as-is; if you run
> this through Frollo with the limit set to 400, as distributed with t at h,
> you get a zigzag mess; if you increase the limit to 800, it works
> perfectly.
>
> (J.D., do you have a local t at h installation and can you perhaps check if
> increasing this limit - line 67 of frollo2.xml - fixes your Copenhagen
> tile also?)
>
> Now what can we do about this? 80n, do you think you can modify Frollo
> to not break ways that are too long? If that is not possible, then I
> would be tempted to count the length of coastline ways created by
> close-areas.pl and somehow trigger bypassing of Frollo if the number is
> too big. We could also try and increase the max number again, which
> would cause Frollo to be aborted in these cases and should ideally lead
> to the same effect (bypassing Frollo). Another option is telling the
> XSLT engine that it should care for "possible endless recursion", but I
> think this only works with xsltrans and not xmlstarlet.
>
> The auto-generated coastline way in the Hebrides can easily be 2,500
> segments or longer for one level-12 tile. Unfortunately I do not see how
> I could easily break this up in close-areas.pl and not ruin Inkscape's
> filling algorithm.
>
>
> --
> Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'
>
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