[Tilesathome] New preprocessor - area center

[Knut Arne Bjørndal]

On Fri, Sep 12, 2008 at 10:52:43AM +1200, Rob Reid wrote:
> Jiri Klement wrote the following on 12/09/2008 01:47:
> > I've added the area center preprocessor to svn. For now it's used only
> > by XSLT. XSLT use different algorithm for area center calculation than
> > orp, so problems with neighbouring tiles described by spaeth already
> > exists for XSLT users. So not big deal if Java is not available and
> > area-center preprocessor can't be used.
> To me it does seem like a big deal, surely if we have a process that is 
> know to cause inconsistencies in the map we should be trying to fix it 
> not implement an additional process that adds more inconsistencies 
> depending on what software clients have installed.
> The idea of a preprocessor for this seems like a good one to me 
> providing its output is used in both orp and XSLT and resolves the 
> inconsistency. I got the impression from when Knut did the area center 
> algorithm in XSLT that it was a pain to implement and I imagine it would 
> be as much pain again to refine it with any improvements to the 
> algorithm so moving this process into the preprocessing stage where we 
> can chose what language to implement it in seems sensible.

I don't think moving this, which really is a part of the rendering
process, out from the renderer is such a good idea. Sure, for t at h we
can put in yet another language, but it makes reproducing something
that looks like the t at h output in SVG even harder, and it's already
too many steps. Not to mention making it work in something like
osmarender-frontend.

The problem with refining the algorithm as it's currently implemented
is A) coming up with the actual refinements and B) finding the time to
do it. B really is the problem, and also the reason I haven't fixed
the areacenter implementation in or/p. Getting areacenter to work was
quite a bit of work, but it's much easier to change small parts than
it is to come up with a way to do the whole thing from scratch.

-- 
Knut Arne Bjørndal
aka Bob Kåre
bob+osm at cakebox.net
bobkare at irc
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