GeoTIFF overviews / TILEINDEX / Large dataset performance

[Frank Warmerdam]

On 6/13/05, Ed McNierney <ed at topozone.com> wrote:
> There is a separate, independent effect due to the resampling of the
> source data.  It is more expensive to resample an image ("zoom out" on
> it) than to display it at "native" resolution.  So to create the most
> efficient source data for any given map request, you would (ideally)
> read as few files as possible AND resample each file as little as
> possible.

Ed,

This is true, but this effect is reduced by building "in image" overviews
since the required resolution of image data may be approximately available. 

Best regards,
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