[postgis-devel] [PostGIS] #1119: [raster] Modify ST_MapAlgebra so that expressions can refer to any band

[PostGIS]

#1119: [raster] Modify ST_MapAlgebra so that expressions can refer to any band
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 Reporter:  pracine         |       Owner:  pracine              
     Type:  enhancement     |      Status:  new                  
 Priority:  low             |   Milestone:  PostGIS Raster Future
Component:  postgis raster  |     Version:  trunk                
 Keywords:                  |  
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Comment(by pracine):

 Important to note that as soon as references are made to other band than
 1, nodata value alternative expressions should be used when ANY of the
 raster value used in the expression is nodata. E.g. if the expression is
 'rast1[2] + rast1[1] * rast2' in the two rasters ST_Mapalgebra(), then
 'nodata1expr' is used instead of 'expression' as soon as one of 'rast1[2]'
 OR 'rast1[1]' is nodata and 'nodatanodataexpr' is used as soon as
 ('rast1[2]' OR 'rast1[1]' is nodata) AND 'rast1[1]' is nodata.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1119#comment:4>
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