Re: [Boost-users] [geometry] Buffer multi-linestring with different distances

Subject: Re: [Boost-users] [geometry] Buffer multi-linestring with different distances
From: Renato Silveira (silveira.ren_at_[hidden])
Date: 2015-03-26 15:58:12

Thank you! I will test this and post a feedback.

Em quinta-feira, 26 de março de 2015, Barend Gehrels <barend_at_[hidden]>
escreveu:

> Hi Renato,
>
> Renato Silveira schreef op 26-3-2015 om 4:01:
>
>> Is it possible to buffer a multi-linestring where each linestring has his
>> own distance to buffer?
>>
>> Something like this:
>> http://docs.qgis.org/2.2/en/_images/variable_buffer.png
>>
>> Thank you in advance
>>
>
> Yes this is, somehow, possible, with some reservations.
>
> The design of the library allows doing these kind of things. But for this
> specific problem it is not yet convenient, and requires point comparisons.
> In case of linestrings, if they intersect (like in your example), that
> might cause some problems.
>
> You can create your own distance-strategy. In that strategy, in the apply
> method, you should check the two input points. Depending on which input
> linestring the points are part of, you could specify another distance.
> See for example the file buffer_distance_symmetric.hpp , which contains
> the default symmetric distance strategy. Using that as a starting point,
> you might experiment.
>
> I did not test this myself. Please report if it works or if there are
> problems.
>
> This will be enhanced in a future release.
>
> Regards, Barend
>
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-- 
*Renato Silveira*
     Ph. D. in Computer Science
     Informatics Institute - UFRGS
     Porto Alegre - RS - Brazil
     http://www.inf.ufrgs.br/~rsilveira