[postgis-devel] [PostGIS] #1268: [raster] ST_MapAlgebraExpr for 2 rasters

[PostGIS]

#1268: [raster] ST_MapAlgebraExpr for 2 rasters
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 Reporter:  dustymugs       |       Owner:  dustymugs    
     Type:  task            |      Status:  assigned     
 Priority:  medium          |   Milestone:  PostGIS 2.0.0
Component:  postgis raster  |     Version:  trunk        
 Keywords:                  |  
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Comment(by dustymugs):

 Replying to [comment:2 bnordgren]:
 > I notice that the expression defaults to null. What does that mean?
 "rast1+rast2"? I think it may make more sense to say "expression text NOT
 NULL".
 >

 I set "expression" to default to NULL as we don't want to make any
 assumptions for the end user.  Setting the "expression" to "rast1 + rast2"
 is no better to me than using "1" or "255" as the function doesn't know
 what the user wants.  So, NULL is the default, which means for two pixels
 of the same coordinates the output pixel's value will be set to NODATA.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1268#comment:4>
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