[Gdal-dev] Re: Rendering optimization [Re: Looking for huge vector dataset]

Schuyler Erle schuyler at nocat.net
Thu Mar 8 00:01:34 EST 2007

* On  6-Mar-2007 at 11:55PM PST, Mateusz Loskot said:
> >> 
> >> 1. load the whole geometry data into memory, into simple
> >> structures  (arrays) - this is similar to how Manifold works
> > 
> > This is doomed to lead into problems once you try to open a theme
> > with 5 million polygons...
> Yup, in many cases it is.  However, both approaches introduce some
> problems.  In all-in-memory approach, the obvious assumption is a
> user has a *lot* of RAM space, 4-8 GB.  But in turn, it provides the
> fastest access to features (accessing RAM is faster than disk or
> network).

This is sort of a blue sky idea, but we build overviews of rasters for
exactly this sort of purpose. I can easily imagine designing some kind
of OGR-based tool that constructs a directory of progressively
generalized versions of a master vector dataset according to a
hierarchy of scales, and then offers an access API that selects the
generalization for a scale appropriate to the task at hand. I can't
speculate whether this sort of tool would belong in GDAL/OGR the same
way that gdaladdo etc. does.


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