[postgis-users] Closing polylines

[Nicolas Ribot]

Hi George,

If the segments are touching each other, like in your sample data, indeed
topology could help a lot to rebuild closed lines.

Here, on this sample, st_polygonize is giving great results. It connects
segments of the same contour and fill it to generate a polygon.
Its exteriorRing gives the actual contour:

select elev, st_exteriorRing(st_geometryN(st_polygonize(geom), 1))
from seg
group by elev;

Do you have some gaps for some contour lines, or they are all connected ?

Nicolas

On 16 May 2012 16:35, Nicolas Ribot <nicolas.ribot at gmail.com> wrote:
> Hi,
>
> I will have a look at it.
>
> Nicolas
>
> On 15 May 2012 11:17, george wash <gws293 at hotmail.com> wrote:
>> Sorry Nicolas, the attachment is in a normal dump format, not shapefile
>> format....
>>
>> _______________________________________________
>> postgis-users mailing list
>> postgis-users at postgis.refractions.net
>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>
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