null shapes (was Re: WIP-pyshapelib-Unicode issues)

[Bernhard Reiter]

On Monday 14 January 2008 16:19, Bram de Greve wrote:
> Oh, I was under the assumption you were talking about shapefiles
> _without_ records =)
>
> "cool, I saw some of the commits happening, but hunted the /empty shape
> file/ problem. (Does somebody know, btw, if such a shape file is
> legitimate at all?)" [emphasis is mine]

Ah, sorry for the confusion. At least we've got it clarified.

> At the bottom of page 5 of the specs
> (http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf), it states:
>
> "A shape type of 0 indicates a null shape, with no geometric data for
> the shape.  Each feature type (point, line, polygon, etc.) [this would
> be the type of the /file/, Bram] supports nulls - it is valid to have
> points and null points in the same shapefile."
>
> So, yes, the example shapefile is legitimate. There are actually 109
> null shapes in that file (on 4962 shapes in total).

Very good to know! Thanks a lot for looking this up!
I guess we should produce an example shapefile having one null element
and one with points and add a unittest based on this file.
Is it easy to create such a shapefile with shapelib?

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