[postgis-users] FileGDB curves

Andy Colson andy at squeakycode.net
Wed Nov 12 06:56:40 PST 2014

Mapserver displays it the same way:


The data looks like:

gis=# select st_AsText(the_geom) from streets where gid = 11517;
-[ RECORD 1 
st_astext | MULTILINESTRING((-10344354.4038468 
5608573.22422463,-10344363.9860388 5608565.68874797,-10344398.9885982 
5608528.81799097,-10344438.5518419 5608468.68094317,-10344404.2129173 
5608265.5414558,-10344355.0291817 5608227.92219317,-10344239.0250123 
5608196.3261761,-10344230.7760714 5608197.59004929,-10344187.3835781 

So I'm assuming that its a convert problem, not a display problem.

I'm not sure how to use ST_LineToCurve.  This is a road layer and 
everything is a MULTILINESTRING, I can't tell the straight from the 
curves.  Can I?



On 11/12/2014 3:58 AM, Rémi Cura wrote:
> Hey,
> first qgis can't deal with curve (i think),
> so your data may be curved in your postgis but the visualisation would
> be incorrect
>   so if you are going to see some curve in qgis, you have to convert the
> curve to approximate theim using
> http://postgis.net/docs/ST_CurveToLine.html,
> then display the geom
> (you can do this in a view if you don't want to duplicate data)
> Now if you are really really sure that data in postgis is bad (use
> ST_AsTExt(geom) for example to see if anything look like curve)
> Either you approximate your curve with multiline and convert it back to
> curve with postgis
> (http://postgis.net/docs/ST_LineToCurve.html)
> Or you have to go the long way and pass the curves as attributes, and
> reconstruct it afterward.
> This seems like a very bad idea.
> I'm afraid curve support is very very limited in all gis tools.
> Cheers,
> Rémi-C
> 2014-11-12 0:00 GMT+01:00 Andy Colson <andy at squeakycode.net
> <mailto:andy at squeakycode.net>>:
>     Hi All,
>     Not sure where the best place to ask this, so I'll start here.
>     I have a FileGDB that contains some curved lines, I import it into
>     PostGIS and they come out as chopped off Multiline.
>     Here are some screen shots to help explain:
>     Here is arc viewing the .gdb:
>     http://testmaps.camavision.__com/arc.png
>     <http://testmaps.camavision.com/arc.png>
>     Here is qgis viewing PostGIS:
>     http://testmaps.camavision.__com/qgis.png
>     <http://testmaps.camavision.com/qgis.png>
>     I tried to get arcCatalog to export to shapefile, but something went
>     bad and I cannot even look at the .shp files.
>     Any hints how I can get the curve back?
>     Thanks for your time,
>     -Andy

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