[gdal-dev] RFC 29: OGR Set Desired Fields

[Frank Warmerdam]

Tamas Szekeres wrote:
> Martin,
> 
> I didn't follow all conclusions made earlier in this thread, but I don't 
> think it makes much sense to enable/disable the special fields since 
> those are derived from the attributes of the feature instead of fetching 
> the values physically from the data source. For example OGR_STYLE 
> corresponds to OGRFeature::GetStyleString() which can provide a 
> meaningful value even if the styles are not handled/supported by a 
> particular driver.

Tamas,

Geometry is generally derived from the physical data source, and knowing
that it can be ommitted can save substantial io and processing.  I must
confess this is less obvious with regard to styles.  I can *imagine*
styles being expensive to collect and form in some cases but I can't
think of any existing driver collecting the style string is particularly
expensive.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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