[postgis-users] curves geometries and topology

[Reijer Copier]

Thanks!

We are currently considering using PostGIS Topology only to maintain a 
topology aware copy of the data (to be used for analyses where topology 
matters) and use the original geometry (containing circular strings) 
when we have to (re)generate output geometry.

BTW: Is cgal/sfcgal going to replace geos eventually? It would be great 
if this limitation (= curved geometries being a second class citizen) 
was somehow lifted in future versions PostGIS.

Regards,

Reijer Copier
IDgis bv

Volg IDgis op LinkedIn! <http://www.linkedin.com/company/idgis>
On 14-4-2014 19:15, Rémi Cura wrote:
> The problem is going to be precision.
>
> If this is important for you you may want to switch to cgal which 
> support arbitrary curve in arrangment (from memory)
>
> If precision is not important, you can easily add an uggly fix : add 2 
> triggers to edge table that
> _when something want to access an edge, convert it to linestring
> _when something want to write an edge, convert it to your curve model
>
> Cheers,
> Rémi-C
>
>
> 2014-04-14 17:10 GMT+02:00 Eric Ladner <eric.ladner at gmail.com 
> <mailto:eric.ladner at gmail.com>>:
>
>     As long as they are simple circles, you should be able to convert
>     back and forth between curves and lines.  Splines, beziers, et al,
>     are probably not going to work at all and would need to be
>     approximated as lines.
>
>     http://boundlessgeo.com/2012/01/getting-curvey/
>
>
>     On Mon, Apr 14, 2014 at 8:02 AM, Reijer Copier
>     <Reijer.Copier at idgis.nl <mailto:Reijer.Copier at idgis.nl>> wrote:
>
>         Dear list,
>
>         According to the documentation, PostGIS Topology only supports
>         edges made out of linestrings. However, we are currently
>         working on a dataset that contains lots of curved geometries.
>         It would be great if we could build topology based on those
>         curved geometries without having to convert them to
>         linestrings first. Is this possible? If not, what is the best
>         way to deal with this situation?
>
>         -- 
>
>         Kind regards,
>
>         Reijer Copier
>         IDgis bv
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>
>
>     -- 
>     Eric Ladner
>
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