[gdal-dev] Is GDAL prepared for this?

Frank Warmerdam warmerdam at pobox.com
Mon Jul 18 11:52:44 EDT 2011


2011/7/18 Jorge Arévalo <jorge.arevalo at deimos-space.com>:
> Hello,
>
> Is GDAL prepared for not equally sized tiled rasters? I mean this
> http://dl.dropbox.com/u/6599273/irregularly_tiled_raster_coverage.png
>
> I think if my raster coverage has that arrangement, I can get rid of
> the GDAL "block" concept. Am I right?
>
> Many thanks in advance, and best regards


Jorge,

GDAL can only expose regular blocking to applications and only use
regular blocking in the block cache.  So if you format has irregular
blocking you wlil need to handle the blocking all within your driver.

The irregularity of the blocks was not entirely clear from the
picture.  If the only irregularity is partial blocks on the right
or bottom then that is not a problem.  You can just treat that
as larger - extending beyond the dataset edge and the
contents outside the dataset are irrelavent.

Also, missing tiles are fine.  We normally just treat them as
having some background value when they are read.  NODATA
pixel values, masks or alpha bands can be used to indicate
areas where there is no real data (missing blocks, etc).

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Software Developer


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