[postgis-devel] [PostGIS] #593: [raster] Add a ST_BandIsNoData function

[PostGIS]

#593: [raster] Add a ST_BandIsNoData function
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 Reporter:  pracine         |       Owner:  pracine      
     Type:  task            |      Status:  new          
 Priority:  medium          |   Milestone:  PostGIS 2.0.0
Component:  postgis raster  |     Version:  trunk        
 Keywords:                  |  
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 Returns true if and only if the band is filled only with nodata values.

 This function is usefull to optimize many functions.

 This function requires a new flag (similar to the hasnodatavalue flag) to
 be set a the band level.

 Change to the loader are also required. Any editing function changing a
 pixel value from nodata to with data should also reset the flag.

 We might want to add a ST_ResetBandISNoData function later.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/593>
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