Indexed Shapefile vs. PostGIS

[Stephen Woodbridge]

Schuyler Erle wrote:
> * On 24-Aug-2005 at  1:46PM PDT, Ethan Alpert said:
> 
>>You can also use shptree to generate a spatial index file (QIX) which
>>mapserver will use to fairly efficiently display the data.
> 
> 
> I've found that the QIX support isn't sufficient to speed up access to
> really large shapefiles, especially if you're doing any kind of
> attribute filtering. I'd love to know why this is.
> 
> SDE
> 
Well, the QIX is a spatial index, not an attribute index. But someone 
might want to check the source code and see if attribute filtering makes 
use of the subset of spatial objects or just dumbly scans all the 
attributes then rejects based on spatial criteria.

-Steve W.