[postgis-devel] Re: [postgis-users] PointM, PolyLineM, PolygonM, ...

strk at refractions.net strk at refractions.net
Thu Sep 23 09:17:35 PDT 2004


Ok.
I've modified pgsql2shp to accept two new switches to control
output type:
	-m for XYM
	-z for XYMZ (alias for -d, kept for backward compatibility)

Semantic is kept.
Support is still missing in shp2pgsql (M values in shapefile are discarded)

--strk;

On Thu, Sep 23, 2004 at 03:19:54PM +0200, Pierrick Brihaye wrote:
> Hi,
> 
> strk at refractions.net a écrit :
> 
> >Ok. So your vote is: respect semantics, even if it's a waste of space.
> 
> Definitely !
> 
> >>BTW : how would you consider a missing Z coordinate ? A "null" (i.e. 
> >>"not applicable") behaviour would be very nice, but wouldn't it make the 
> >>stuff more complicated ?
> >
> >I guess you mean a missing M coordinate...
> 
> No, a real Z coordinate. For example, TypeM <-> X,Y,?,M
> 
> >I'm afraid it'll have to be 0.0 as NaN coordinates are invalid.
> 
> That was the question :-) No objection from my part : I consider this 
> design as being better than to map M to the third coordinate.
> 
> Any other advice ? This point of design looks crucial, doesn't it ?
> 
> Cheers,
> 
> -- 
> Pierrick Brihaye, informaticien
> Service régional de l'Inventaire
> DRAC Bretagne
> mailto:pierrick.brihaye at culture.gouv.fr
> +33 (0)2 99 29 67 78
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