[teiid-issues] [JBoss JIRA] (TEIID-4580) ST_PointOnSurface returns point on the boundary of the polygon

[Steven Hawkins (JIRA)]

     [ https://issues.jboss.org/browse/TEIID-4580?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steven Hawkins closed TEIID-4580.
---------------------------------


> ST_PointOnSurface returns point on the boundary of the polygon
> --------------------------------------------------------------
>
>                 Key: TEIID-4580
>                 URL: https://issues.jboss.org/browse/TEIID-4580
>             Project: Teiid
>          Issue Type: Bug
>          Components: Query Engine
>    Affects Versions: 9.x, 8.12.7.6_3
>            Reporter: Andrej Šmigala
>            Assignee: Steven Hawkins
>             Fix For: 9.1.2, 9.2, 8.12.9.6_3
>
>
> Calling ST_PointOnSurface with a polygon argument returns one of the points of the polygon boundary. 
> E.g.
> {code:sql}
> SELECT ST_AsText(ST_PointOnSurface(ST_GeomFromText('POLYGON ((67 13, 67 18, 59 18, 59 13, 67 13))')));
> {code}
> returns {{POINT (67 13)}}
> The spec says
> bq. PointOnSurface( ):Point—A point guaranteed to be on this Surface.
> which might not be completely clear, but [several|http://gis.stackexchange.com/questions/76498/how-is-st-pointonsurface-calculated] [sources|http://workshops.boundlessgeo.com/postgis-intro/geometry_returning.html] indicate that "on this surface" means _inside_ the surface.
> When running the same query against a postgis instance (not through teiid), the result is {{POINT(63 15.5)}}, which is actually inside the polygon.



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