Quoting Scott Ellington <scottellington@comcast.net>:

> scottell=# select line_interpolate_point(the_geom,0.5) from
> road_100_tiger ;
> ERROR:  line_interpolate_point: 1st arg isnt a line
> 
> I assume this is because my geometry is of type MULTILINESTRING instead
> of LINESTRING.  Is it possible for me to use my multilinestring data in
> this function?  If not, my thinking was that perhaps I could extract the
> LINESTRINGs on the fly.  Is there any built-in functionality to do this?


select line_interpolate_point(geometryN(the_geom,1),0.5) from
road_100_tiger ;

GeometryN( <multi geometry> , n) pulls the nth sub-geometry out of the given 
MULTI* or GEOMETRYCOLLECTION.

dave



