[postgis-users] why is this poly invalid?

[Nicolas Ribot]

> hi all
>
> Several polygons in our DB are being flagged as invalid by ST_IsValid,
> but I don't really understand why.  Here's one of them as WKT:
>
> "SRID=4326;POLYGON((144.196 -14.2479,144.196 -14.2607,143.736483333333
> -14.2991166666667,143.7384 -14.2987333333333,143.911533333333
> -14.4488166666667,144.037866666667 -14.4488166666667,144.037866666667
> -14.32515,144.119833333333 -14.3589833333333,144.196 -14.2479))"
>
> The documentaion of ST_IsValid could be a little more helpful:
>
> "ST_isvalid(geometry)
>
>      returns true if this geometry is valid."
>
> The poly is self intersecting, but ST_IsSimple returns true - that can't
> be right can it?
>
>

hello,
No, self-intersecting polygons are not valid in postgis.
Try to edit it to correct the intersection.

Nicolas