[postgis-devel] [PostGIS] #1764: overviews not marked as same alignment though main table is

[PostGIS]

#1764: overviews not marked as same alignment though main table is
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 Reporter:  robe    |       Owner:  dustymugs    
     Type:  defect  |      Status:  assigned     
 Priority:  medium  |   Milestone:  PostGIS 2.0.1
Component:  raster  |     Version:  2.0.x        
 Keywords:          |  
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Comment(by dustymugs):

 As the rasters which uncovered the problem described in this ticket, the
 following describes the attributes of the rasters in a generic manner.

 Raster 1
 {{{
 width: 100
 height: 100
 scale-x: 1
 scale-y: -1
 skew-x: 0
 skew-y: 0
 upperleft-x: 0
 upperleft-y: 0
 }}}

 Raster 2
 {{{
 width: 100
 height: 100
 scale-x: 1
 scale-y: -1
 skew-x: 0
 skew-y: 0
 upperleft-x: 100
 upperleft-y: 0
 }}}

 If the above two rasters are loaded in with raster2pgsql, the tiles are
 aligned.  But for an overview factor of 3 (and probably anything else
 where the division of the width/height by the overview factor results in a
 repeating decimal), the alignment of the overview will not be aligned.

 When creating overviews, raster2pgsql treats each input raster
 independently of all other input rasters.  This does not work for
 situations like this.  Instead, it may be better to get the overall extent
 for the set of input rasters and then process each individual input raster
 based upon the overall extent.

 The one issue here is what to do if the input rasters are NOT of the same
 scale and skews?  Use the "old" method (the current method) or fail?

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1764#comment:8>
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