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

[PostGIS]

#593: [raster] Add a ST_BandIsNoData function
----------------------------+-----------------------------------------------
 Reporter:  pracine         |       Owner:  jorgearevalo 
     Type:  task            |      Status:  assigned     
 Priority:  medium          |   Milestone:  PostGIS 2.0.0
Component:  postgis raster  |     Version:  trunk        
 Keywords:                  |  
----------------------------+-----------------------------------------------

Comment(by pracine):

 > These are the 2 entries for storing new raster data. In raster2pgsql.py
 we must set the flag when dealing with offdb bands. The rest of the cases
 are managed by the 2 core functions mentioned (rt_band_set_pixel,
 rt_band_set_nodata).
 >
 > Am I missing something?

 raster2pgsql.py do not do this only for off-db raster. It does it for
 every rasters. And it must do it while reading the file without affecting
 performance.

 There should also be a boolean option to rt_band_set_nodata (and
 ST_SetBandNodata) to recheck every pixels. The default behavior is always
 to avoid this, unless the users explicitely ask for a recheck (with the
 option). We could add this option to ST_SetValue also.

 Really, by default we try to avoid rechecking as this will decrease
 performance and is required only on edited coverage. In most situations
 the flag set by the loader will never have to change (unless there is
 edition). Even in the case of edition, the recheck must happen only on
 request.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/593#comment:12>
PostGIS <http://trac.osgeo.org/postgis/>
The PostGIS Trac is used for bug, enhancement & task tracking, a user and developer wiki, and a view into the subversion code repository of PostGIS project.