[postgis-tickets] [PostGIS] #3023: Create ST_ClusterIntersecting / ST_ClusterWithin Functions

[PostGIS]

#3023: Create ST_ClusterIntersecting / ST_ClusterWithin Functions
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 Reporter:  dbaston      |       Owner:  dbaston      
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.2.0
Component:  postgis      |     Version:  trunk        
 Keywords:               |  
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Comment(by robe):

 dbaston,

 Even though aggregates can be pains to upgrade, they are only pains if
 people use them in views or SQL functions (in sql functions, I'm not
 absolutely sure they are checked, though I suspect they are).  That said
 if you think this function will never be embedded in a view, I wouldn't
 worry too much about it.

 Have the array option is good anything though because most aggregate
 functions we implement have both an array version and an aggregate
 version.  Take a look at ST_Union for example.
 http://postgis.net/docs/manual-2.1/ST_Union.html  So we could start off
 with an array version and then create an aggregate later.

 Two benefits I see with having an aggregate version
 1) the outward facing use, in many cases will be easier for the end user
 to encorporate

 2) You can leverage the state transitioning machinery of PostgreSQL
 aggregation like ST_Union, ST_Collect (and various raster aggregates do)
 to better handle a larger number of geometries.  (this part I'm not sure
 about but pramsey, strk, or dustymugs would have a better clue if that
 applies here)

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/3023#comment:7>
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