[postgis-users] Getting argument of AND must not return a set, when trying to calculate the intersection of a end of a multiline and a polygon

[Stephen Woodbridge]

Dave,

st_dump returns a set.
you might want to use st_geometryN(rt.the_geom, 1) instead.

-Steve

On 5/16/2013 7:05 PM, Dave Potts wrote:
> Hi,
>
> I am trying to find the results of an intersection between a multi line
> string and a polygon,  I had assumed that saying something
> like
>
> select rt.source,
> av.geom,st_astext(st_startpoint((st_dump((rt.the_geom))).geom)) from
> route_table rt ,
> avoid_areas av
> where av.valid=true and rt.parent_port_id=80360 and
> st_within(av.geom,st_startpoint((st_dump((rt.the_geom))).geom)) =true
>
> might work where rt.the_geom is a multiline  and av.geom is a polygon
>
> but I get the error,
> ERROR:  argument of AND must not return a set
> LINE 4: st_within(av.geom,st_startpoint((st_dump((rt.the_geom))).geo
>
> any idea what I am doing wrong?
>
> Dave
>
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