[Gdal-dev] Imagine overviews option

[Garrett Potts]

Hello FRank:

Understood. Thank you for the information.


Take care

Garrett
On Sep 16, 2005, at 12:57 PM, Frank Warmerdam wrote:

> On 9/16/05, Garrett Potts <potts at cfl.rr.com> wrote:
>
>> Hello FRank and others:
>>
>> Actually it seems if anything were to be added it would be best to
>> add it to the XML option string for the hfa dataset???
>> I am not sure if frank likes this or not but this would give a
>> generic way, without changing any current interfaces, of specifying
>> writer specific overview dataset creation options.
>>
>>    <Option name='HFA_USE_RRD' type='boolean' description='Use
>> external rrd file for overview building, default NO'/>
>>
>> Not sure if this is what the create options was intended?  If not
>> then maybe some other metadata NAME could be added for the HFA
>> specific way of creating an overview?
>>
>
> Garrett,
>
> The problem is that creation options are for information needed when
> creating the .img file.  But creating overviews is not part of the  
> Create()
> or CreateCopy() methods.  It is a separate operation that might be
> never be done, might be done later, or might be done in a separate
> process run.
>
> If I were to allow this to be passed into the Create() method, then I
> would have to figure out somewhere in the .img file to stash this
> preference so that I could find it again later when it is time to  
> create
> overviews.   That is possible, but it seems ... messy.  And it  
> would not
> extend well to other formats where I cannot just add arbitrary data
> in the format.
>
> 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 Programmer for  
> Rent
>