Performance of Scanning a Quadtree Index

[Frank Warmerdam]

Daniel Morissette wrote:
> Frank Warmerdam wrote:
>>
>> I haven't dug into this, but I think MapServer pulls the features from
>> the shapefile in the order they are identified traversing the spatial
>> index.  This *could* mean relatively random fetching depending on the
>> spatial coherence (or lack thereof) of the records in the shapefile.
>>
> 
> Frank,
> 
> I could be wrong, but my understanding is that MapServer reads the 
> shapes in the shapefile order all the time. If a .qix file is present, 
> then an array of bits is used to tag the shape ids to load, and then the 
> shapes are read in order of shape id.

Daniel,

Ah, and there is the danger of a theory without investigation. :-)

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    | President OSGeo, http://osgeo.org