[Qgis-user] Is QGIS showing the records with geometry NULL

[Andrea Peri]

Hi jukka.
I guess empty geometry is a not null geometry.
Il 26 mag 2016 4:34 PM, "Rahkonen Jukka (MML)" <
jukka.rahkonen at maanmittauslaitos.fi> ha scritto:

> Hi,
>
> We spent some time with empty geometries in OpenJUMP and I attach some
> test data from those experiments. Feel free to use it in the QGIS feature
> request. Zip contains point, line, and polygon shapefiles, each having 8
> features but only one feature with geometry.  From the WKT files you can
> see that there are actually different kind of empty geometries. I even did
> not bother to think about Z, M, and ZM geometries.
>
> POINT EMPTY
> MULTIPOINT EMPTY
> LINESTRING EMPTY
> MULTILINESTRING EMPTY
> POLYGON EMPTY
> MULTIPOLYGON EMPTY
> GEOMETRYCOLLECTION EMPTY
>
> One may say that empty is always just empty but one needs also to think
> what happens if user copies POLYGON EMPTY and tries to paste it into a
> point layer. Should copy be denied or empty geometry converted into POINT
> EMPTY? For OpenJUMP that does not matter because it can handle all kind of
> geometries on the same layer. However, saving POINT EMPTY into polygon
> shapefile may fail and therefore OpenJUMP can convert even empty geometries
> like POINT EMPTY ->POLYGON EMPTY.
>
> -Jukka Rahkonen-
>
> Andrea Peri wrote:
>
> Hi Jukka,
> yes is exactly this the question.
>
> The QGIS don't show any record with null geometry so is impossible for me
> to add a geometry to it. Or delete it definitivelly.
>
> But the record with null geometry is however saved when I export the
> shapefile from qgis.
>
> So the QGIS show me 14 records but export a shapefile with 16 records
> (2 records has null geometry).
>
> So when load it in a spatialite or on a postgis environment or open it
> using another GIS like arcview3 from esri.
> I see this two more records with null geometry.
>
> AFAIK this is a chaotic situation for who work using qgis and produce a
> shapefile to distribute to other users that has other gis softwares.
>
> A.
>
>
> 2016-05-26 10:24 GMT+02:00 Jukka Rahkonen <
> jukka.rahkonen at maanmittauslaitos.fi>:
> > Nicolas Cadieux <nicolas.cadieux at ...> writes:
> >
> >>
> >>
> >> Hi,
> >> Is it possible that the 2 missing records were deleted in another GIS?
> > There is an issue with deleting records in shape file as there are
> > many ways to do that.  If the record were deleted in another GIS, they
> > may show up (or
> > not) in another software. Could that be it...
> >> Nicolas
> >
> > Hi,
> >
> > I suppose that Andrea means a valid situation with real existing
> > features which just do not have geometry. They are valid in shapefiles
> > but many GIS software have difficulties in dealing with them.
> > Naturally they cannot be showed on the map and spatial queries can't
> > find them but they should be found from attribute view and be editable
> there.
> >
> > -Jukka Rahkonen-
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>
>
> --
> -----------------
> Andrea Peri
> . . . . . . . . .
> qwerty àèìòù
> -----------------
>
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