[postgis-tickets] [PostGIS] #2210: [raster]: ST_Envelope for raster that considers only data values

[PostGIS]

#2210: [raster]: ST_Envelope for raster that considers only data values
-------------------------+--------------------------------------------------
 Reporter:  robe         |       Owner:  dustymugs    
     Type:  enhancement  |      Status:  assigned     
 Priority:  medium       |   Milestone:  PostGIS 2.1.0
Component:  raster       |     Version:  trunk        
 Keywords:               |  
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Comment(by dustymugs):

 Modifying ST_ConvexHull() may be a no-go as that function signature is
 critical for the raster to geometry cast.  From the looks of the docs (and
 the error that forced me to look at the docs)...

 {{{
 Cast implementation functions can have one to three arguments. The first
 argument type must be identical to or binary-coercible from the cast's
 source type. The second argument, if present, must be type integer; it
 receives the type modifier associated with the destination type, or -1 if
 there is none. The third argument, if present, must be type boolean; it
 receives true if the cast is an explicit cast, false otherwise.
 (Bizarrely, the SQL standard demands different behaviors for explicit and
 implicit casts in some cases. This argument is supplied for functions that
 must implement such casts. It is not recommended that you design your own
 data types so that this matters.)
 }}}

 [http://www.postgresql.org/docs/9.0/interactive/sql-createcast.html]

 That definitely will not work for us.  So, different signature?

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/2210#comment:7>
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