[Mapserver-users] Gdaladdo

[Frank Warmerdam]

Omry Yadan wrote:
> Frank,
> By high zoom I meant zoomed in.
> For zoom out, the performance is relatively alright, but some times I get
> very poor time for zoom in.
> I think it's a specific zoom that cause me the problems...
> Maybe the zoom where I get the image around the real maximum resolution,
> with little scaling.
> Does it make sense?

Omry,

Well, it is plausable.  Currently the GDAL ECW driver goes through a
very "general" case requesting the full width of the underlying image if
the requested region is at higher resolution than the actual image - even
just a wee bit.  This is likely what is biting you.

By the way, contrary to what I suggested in my last message, I see the
ECW driver is already optimized for overview access.  I was confused about
the status.

Best regards,

-- 
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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