[gdal-dev] Erdas .img format (HFA) overview troubles

[Frank Warmerdam]

Christiaan Janssen wrote:
> On the page http://www.gdal.org/frmt_hfa.html, it mentions the creation of
> .ovr files under the Creation Issue section. 

Christiaan,

I have removed this inaccurate comment.

> Also, am I wrong in thinking
> the command "gdaladdo -ro test.img 2 4 8" should have at least generated an
> .aux (or .rrd) file and not errored the way it did? Thanks.

The error message was unhelpful, but I presume the issue is that overviews
cannot be generated in a read-only file.  If you would like to file a ticket
on this, I could look into more appropriate error handling.

I would add, if you wanted ovr support it should be relatively trivial for
you to add it in your local build with a call to initialize the
overview manager at the end of the Open() method.

     poDS->oOvManager.Initialize( poDS, poOpenInfo->pszFilename );

I am hesitant to do this in the mainline code though.

Best regards,
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