[postgis-devel] length{,2d,3d}

[Mark Cave-Ayland]

> -----Original Message-----
> From: postgis-devel-bounces at postgis.refractions.net 
> [mailto:postgis-devel-bounces at postgis.refractions.net] On 
> Behalf Of Martin Daly
> Sent: 25 August 2004 11:36
> To: PostGIS Development Discussion
> Subject: RE: [postgis-devel] length{,2d,3d}
> 
> 
> Mark,
> 
> > This is definitely an interesting issue that you've raised.
> > I've just had a look over the OpenGIS specification and 
> > looking at section 2.1.3.1 it would appear that the entire 
> > spec is only written based on a 2D point :/. The other 
> 
> The attached OGC document (which was adopted some time ago) 
> is an addendum to the Simple Features specification which covers 2.5D.
> 
> Regards,
> Martin


Hi Martin,

Thanks for the pointers, as you suspected I was still looking at just
the original spec PDF. The case of a 2D -> 3D cast doesn't appear to be
a problem, however it looks like there are some interesting functions to
write around the spatial operators, for example collapsing a 3D geom to
2D, calculating the difference, and then interpolating the result back
into 3D.... does GEOS already do this? :)


Cheers,

Mark.

---

Mark Cave-Ayland
Webbased Ltd.
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