[postgis-users] line_interpolate_point complains on 2nd Arg

[Sufficool, Stanley]

I have verified the CASE statements for the line_interpolate_point
(returns .10101010101). My problem evidently was with line_substring
where I was specifying the distance along the line instead of a float
percentage. Problem solved.

It would be great if PostGIS had a line_interpolate_point_offset(line,
percent, offset, angle) for doing this and offsetting the point to the
left (angle = -90)/right (angle = 90) of the line segment to which it
was matched.

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net 
> [mailto:postgis-users-bounces at postgis.refractions.net] On 
> Behalf Of Kevin Neufeld
> Sent: Tuesday, March 11, 2008 7:16 PM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] line_interpolate_point complains 
> on 2nd Arg
> 
> 
> Are you sure you've verified the range is [0,1]?  Try your query with 
> just selecting the case statements:
> SELECT
>   CASE WHEN ... END AS param1,
>   CASE WHEN ... END AS param2,
> ...
> FROM countrystreets ...
> 
> If so, can you isolate the geometry that is causing the 
> error?  If it's 
> not too large, post the WKT or hexstring representation here. 
> 
> -- Kevin
> 
> Sufficool, Stanley wrote:
> > I have been attempting to find a SQL only geocode query for our 
> > specific dataset and arrived at the following. 
> line_interpolate_point 
> > complains that the 2nd param is out of range [0,1]. I verified that 
> > the value returned is 0.101010101010101 (float8). I have 
> replaced the 
> > "CASE" with this value and it still complains.
> >
> > The query interpolates the point, grabs the line segment 
> and offsets 
> > the point to the left/right of the street segment by 50 units.
> >
> > PostgreSQL 8.0.15, Gentoo Linux x86, PostGIS 1.3.1
> >
> > SELECT 
> > 	translate(
> > 		line_interpolate_point (
> > 			the_geom, 
> > 			CASE WHEN ( (320 % 2) = (l_add_from % 2) )
> > 				THEN ( (320 - l_add_from) / (l_add_to -
> > l_add_from) )
> > 				ELSE ( (320 - r_add_from) / (r_add_to -
> > r_add_from) )
> > 			END::float
> > 		),
> > 		CASE WHEN (320 % 2) = (l_add_from % 2) THEN 
> > 				(x(line_substring(the_geom, 
> > 				length(the_geom) * ( (320 - l_add_from)
> > / (l_add_to - l_add_from) ),
> > 				length(the_geom) * ( (320 - l_add_from)
> > / (l_add_to - l_add_from) ) + 50)))
> > 			ELSE
> > 				-(x(line_substring(the_geom, 
> > 				length(the_geom) * ( (320 - r_add_from)
> > / (r_add_to - r_add_from) ),
> > 				length(the_geom) * ( (320 - r_add_from)
> > / (r_add_to - r_add_from) ) + 50)))
> > 		END,
> > 		CASE WHEN (320 % 2) = (l_add_from % 2) THEN 
> > 				-(y(line_substring(the_geom, 
> > 				length(the_geom) * ( (320 - l_add_from)
> > / (l_add_to - l_add_from) ),
> > 				length(the_geom) * ( (320 - l_add_from)
> > / (l_add_to - l_add_from) ) + 50)))
> > 			ELSE
> > 				(y(line_substring(the_geom, 
> > 				length(the_geom) * ( (320 - r_add_from)
> > / (r_add_to - r_add_from) ),
> > 				length(the_geom) * ( (320 - r_add_from)
> > / (r_add_to - r_add_from) ) + 50)))
> > 		END
> > 	) as address_point,
> > 	CASE WHEN (320 % 2) = (l_add_from % 2) THEN 'LEFT' else 
> 'RIGHT' END 
> > as street_side
> > 	FROM countystreets s 
> > 	WHERE CASE WHEN (320 % 2) = (l_add_from % 2) THEN (l_add_to -
> > l_add_from) ELSE (r_add_to - r_add_from) END > 0
> > 	AND s.pre_dir = 'E'
> > 	AND replace(s.street_name,' ','') = 'PHILLIPS' 
> > 	AND s.street_type = 'ST' 
> > 	AND s.suf_dir = '' 
> > 	AND s.l_zipcode = substr('91761-4230',1, 5) 
> > 	AND (
> > 		320 BETWEEN l_add_from and l_add_to
> > 		OR 320 BETWEEN r_add_from and r_add_to
> > 		)
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