Parallel LineSymbolizer

Hello,

I was looking through mapnik documentation for the following feature:
A line is assigned 2 LineSymbolizers. I would like mapnik to paint them
not one over another, but one next to the other. For example if a road,
which normally looks like

=====================

is assigned colours 'Red' and 'Blue', the result would look like this:

RRRRRRRRRRRRRRRRRRRRR
=====================
BBBBBBBBBBBBBBBBBBBBB

However I couldn't find any clue about any similar feature on the
mapnik.org. Could you tell me if I have overlooked something, please?

The problem is that such thing cannot be done by pre-processig the data,
since the distance between Red and Blue must be independent of zoom.

The motivation is the traditional way of painting Czech tourist trails.
The result should ideally look similar to:
http://www.mapy.cz/#x=134865920@y=138622720@z=12@mm=TTtP

Thank you in advance,
Radek Cernoch


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[Michal Migurski-3]

Radomir,

What you're describing sounds like this ticket:
        http://trac.mapnik.org/ticket/180

It's been in Trac for some time, and I think there's some momentum  
building to get it handled in an upcoming release. It's not there yet,  
though.

-mike.

On May 24, 2009, at 3:37 PM, Radomir Cernoch wrote:

> Hello,
>
> I was looking through mapnik documentation for the following feature:
> A line is assigned 2 LineSymbolizers. I would like mapnik to paint  
> them
> not one over another, but one next to the other. For example if a  
> road,
> which normally looks like
>
> =====================
>
> is assigned colours 'Red' and 'Blue', the result would look like this:
>
> RRRRRRRRRRRRRRRRRRRRR
> =====================
> BBBBBBBBBBBBBBBBBBBBB
>
> However I couldn't find any clue about any similar feature on the
> mapnik.org. Could you tell me if I have overlooked something, please?
>
> The problem is that such thing cannot be done by pre-processig the  
> data,
> since the distance between Red and Blue must be independent of zoom.
>
> The motivation is the traditional way of painting Czech tourist  
> trails.
> The result should ideally look similar to:
> http://www.mapy.cz/#x=134865920@y=138622720@z=12@mm=TTtP
>
> Thank you in advance,
> Radek Cernoch
>
>
> _______________________________________________
> Mapnik-users mailing list
> Mapnik-users@...
> https://lists.berlios.de/mailman/listinfo/mapnik-users
>

----------------------------------------------------------------
michal migurski- mike@...
                  415.558.1610


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Dear Mike,

thank you for the link, it really looks very similar to what is needed.

Nevertheless the small difference is that the offset (especially its +/-
sign) should be determined by mapnik automatically for the Czech tourist
trails purposes. Otherwise the style definition would have to include
the super-set of at least 4 colours used for trails (15 definitions in
total) not mentioning the subsequent problems of drawing the junctions.

Do you think I should add this to the ticket? Or possibly create a new
one?

Thanks,
Radek Černoch

Michal Migurski píše v Ne 24. 05. 2009 v 16:52 -0700:

> Radomir,
>
> What you're describing sounds like this ticket:
> http://trac.mapnik.org/ticket/180
>
> It's been in Trac for some time, and I think there's some momentum  
> building to get it handled in an upcoming release. It's not there yet,  
> though.
>
> -mike.
>
> On May 24, 2009, at 3:37 PM, Radomir Cernoch wrote:
>
> > Hello,
> >
> > I was looking through mapnik documentation for the following feature:
> > A line is assigned 2 LineSymbolizers. I would like mapnik to paint  
> > them
> > not one over another, but one next to the other. For example if a  
> > road,
> > which normally looks like
> >
> > =====================
> >
> > is assigned colours 'Red' and 'Blue', the result would look like this:
> >
> > RRRRRRRRRRRRRRRRRRRRR
> > =====================
> > BBBBBBBBBBBBBBBBBBBBB
> >
> > However I couldn't find any clue about any similar feature on the
> > mapnik.org. Could you tell me if I have overlooked something, please?
> >
> > The problem is that such thing cannot be done by pre-processig the  
> > data,
> > since the distance between Red and Blue must be independent of zoom.
> >
> > The motivation is the traditional way of painting Czech tourist  
> > trails.
> > The result should ideally look similar to:
> > http://www.mapy.cz/#x=134865920@y=138622720@z=12@mm=TTtP
> >
> > Thank you in advance,
> > Radek Cernoch
> >
> >
> > _______________________________________________
> > Mapnik-users mailing list
> > Mapnik-users@...
> > https://lists.berlios.de/mailman/listinfo/mapnik-users
> >
>
> ----------------------------------------------------------------
> michal migurski- mike@...
>                   415.558.1610
>
>
> _______________________________________________
> Mapnik-users mailing list
> Mapnik-users@...
> https://lists.berlios.de/mailman/listinfo/mapnik-users

--
Radomir Cernoch
[phone] / [phone]
Email, Jabber: radomir.cernoch@...

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