[gdal-dev] Is GDAL prepared for this?

[Jorge Arévalo]

Hello,

2011/7/18 Frank Warmerdam <warmerdam at pobox.com>:
> 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.
>

Just what I thought.


> 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.
>

Yes, the picture is only a simplification. The format can store
different size blocks, not only at the right or at the bottom of the
raster coverage. Any number of blocks and any block size are allowed.

> 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).
>

Thanks for the tips :-)

Best regards,
Jorge