[postgis-users] Newbie question - Transfer attributes fromonefeature to another

[Obe, Regina]

You mean like to concatenate all the point field information in one
field in the poly.  Also the below I gave was to create a new set of
data.  To update a poly field by concatenating all the field information
from the points.  Try something like
 
UPDATE table1
SET somefield =  array_to_string(ARRAY(SELECT DISTINCT point.somefield 
            FROM table2 As point 
            WHERE point.somefield > '' AND
ST_Intersects(table1.the_geom, point.the_geom)
    ), ",");
 
Hope that helps,
Regina

________________________________

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Intengu Technologies
Sent: Monday, October 06, 2008 8:08 AM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] Newbie question - Transfer attributes
fromonefeature to another


Regina,

Solution 3 is would work fine, but was hoping for a solution to transfer
the attributes into one field without duplicating the poly.

Thanks for the pointer.



2008/10/6 Obe, Regina <robe.dnd at cityofboston.gov>


	Sindile,
	 
	If a polygon has one or more point features and you want to
transfer the attributes from the point feature to the polygon feature,
then what do you do in cases where there are multiple points in a
polygon
	 
	would you
	 
	1) pick the first one you hit
	2) Sum up, take the max etc. of each
	3) Duplicate the poly for each point?
	 
	In all cases, you will want to do an intersect check
	 
	(solution 1)
	
	SELECT DISTINCT ON(poly.gid) poly.gid, poly.the_geom,
point.somefield1 As somefield1, point.somefield2 As somefield2
	FROM
	table1 As poly INNER JOIN table2 As point
	ON ST_Intersects(poly.the_geom, point.the_geom)
	ORDER BY poly.gid, point.gid;
	 
	(solution to 2 would look something like this)
	SELECT poly.gid, poly.the_geom, SUM(point.somefield1) As
totsomefield1, MAX(point.somefield2) As maxsomefield2
	FROM
	table1 As poly INNER JOIN table2 As point
	ON ST_Intersects(poly.the_geom, point.the_geom)
	GROUP BY poly.gid, poly.the_geom;
	 
	(solution to 3)
	  
	SELECT poly.gid, poly.the_geom, point.somefield1 As somefield1,
point.somefield2 As somefield2
	FROM
	table1 As poly INNER JOIN table2 As point
	ON ST_Intersects(poly.the_geom, point.the_geom)
	 
	Hope that helps,
	Regina
	 
	 
	 
	 

________________________________

	From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Intengu Technologies
	Sent: Monday, October 06, 2008 4:47 AM
	To: PostGIS Users Discussion
	Subject: [postgis-users] Newbie question - Transfer attributes
from onefeature to another
	
	
	I have a polygon (table1) and a point (table2) feature and would
want to transfer attributes from the point feature to the polygon
feature based on whether the point feature is completely enclosed by the
polygon feature.
	The polygon feature can have one or more point features.
	
	How do i transfer the attributes.
	
	
	-- 
	Sindile Bidla
	

	

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-- 
Sindile Bidla



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