[Gdal-dev] Bug in OGDI Driver when accessing tiles (FAILURE: 1: End of selection)

[Reiner Beck]

Frank,
> I am going to apply the following patch.  I think this will avoid
> resetting the window in some cases, but *will* reset it if the
> "current index" isn't pointing to the first line of the window.
> Could you try this and verify it fixes your problem?
thank you that fixes it. I tested both the Matrix and the Image case.
>
> I don't really have test scripts in place for OGDI so I am always
> nervous about making changes in this old code.  It seems to me there is
> substantial opportunities for optimization in the OGDI driver, especially
> for the common case of a program reading the whole source from top to
> bottom in a bunch of 1 scanline rasterio requests.
Well, looking at the amount of fopen/close in the RPF driver for the 
different image parts, there is certainly a heavy impact on how one 
accesses the data. In my case I have to do it always on a tile basis 
(normally 256x256 pixel chunks). As I stated in my previous post, the 
order in which the tiles are accessed are "a bit random". This is to 
speed up processing on my side.
However, I could re-order each request to access the tiles in a 
different order, for example start with the first row of tiles and so on.

Do you think it would speed up the reading process if I re-order the 
tile requests?

BTW, do you know how the NITF files in a CADRG dataset are compressed?

Cheers
Reiner