Performance of Scanning a Quadtree Index

[Steve Lime]

This is correct. Also, if no .qix file is present OR if the bbox requested contains the entire layer bbox then 
the bit array is set to all 1's and feature level bbox filtering is done for everything.

Steve

>>> On 8/29/2007 at 12:20 PM, in message <46D5AACA.6010608 at mapgears.com>, Daniel
Morissette <dmorissette at MAPGEARS.COM> 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