Hi,
1) It should never happen but we are living in a not perfect world and it
happens and will always happen.
2) For some use cases the invalid geometries may be good enough. Typical
examples are polygons with tiny self-intersections or inner circles with only
two vertices (A-B-A). Simplifica
Hi,
sorry, the last point 2 should be a 3 :-(
uwe
Am 10.04.2013 10:24, schrieb Uwe Dalluege:
> Hi Michaël,
>
> do you mean the option
> Options>View/Edit>Prevent edits resulting invalid geometries?
>
> I am not understanding this option.
> What is the use of drawing a selfintersection polygon?
>
Hi Michaël,
do you mean the option
Options>View/Edit>Prevent edits resulting invalid geometries?
I am not understanding this option.
What is the use of drawing a selfintersection polygon?
1. In my opinion a program should never *compute* invalide
geometries like multipolygon if it is not
a valid
Hi Larry,
Thanks for the input,
I followed your suggestion to add a warning in the status bar.
I did the test for the MultiPolygon case only though.
Not sure it is useful in the general case. Maybe it would be
better to make the plugin consistent with the edit tools option
"accept invalid geomet
Hi Martin,
> I just noticed that the code we use for the CombineSelectedFeature plugin
> is very close to GeometryFactory.buildGeometry() method.
> Hence, I checked buildGeomery code and found that in the particular case
> of two adjacent polygons, it will also produce an invalid geometry.
And prob
Hi Martin,
I just noticed that the code we use for the CombineSelectedFeature plugin
is very close to GeometryFactory.buildGeometry() method.
Hence, I checked buildGeomery code and found that in the particular case
of two adjacent polygons, it will also produce an invalid geometry.
I don't know w
Hi Michaël,
Echoing what I think you are proposing:
1) when Combine Selected Features is invoked, a basic topology validity
check is done on the result.
2) Any errors should be reported in the status bar or the Output Window.
3) If an invalid geometry results from building a MultiPolygon, a
Ge
> 2 - I agree that in this case, building a valid GeometryCollection
> is better than building an invalid Multipolygon, even if
> GeometryCollection are much less useful (many operations
> accepting MultiPolygon will fail on GeometryCollection).
> If if no one has any objection, I propose to do the
Hi,
> Is it in OJ possible to check first for valid
> geometries when
> "Combine Selected Features"
> or is this a great problem?
>
> If it is a great problem maybe it is better
> "Combine Selected Features"
> makes always a geometrycollection?
There are several points :
1 - in the step by step pr
Hi Martin, Michaël and Stefan,
thank you very much for this detailed clarification!
Is it in OJ possible to check first for valid
geometries when
"Combine Selected Features"
or is this a great problem?
If it is a great problem maybe it is better
"Combine Selected Features"
makes always a geometr
As Michael and Stefan point out, Polygons in a MultiPolygon must be
edge-disjoint (which another way of stating the formal definition "must
only touch at a finite number of points". If they touched along an
edge, that would cause an infinite number of points to be coincident).
Another way of l
Hi Uwe, Stefan,
OpenJUMP (JTS) is right, this MultiPolygon is not OGC conform
Here is the citation :
Multipolygon
2. The Boundaries of any 2 Polygons that are elements of a MultiPolygon
may not ‘cross’ and may touch
at only a finite number of points. (Note that crossing is prevented by
assertio
Hi Uwe,
I am not sure I would call it a bug. OJ, should (try to) create data
that are OGC conform, but in this case it doesn't. Which means, the case
needs special treatment, but this is not implemented.
That the multi-polygon causes an error is with the OGS SF specification
= correct. However
Hi Stefan,
I am afraid I do not understand :-(
Do you think this is a bug in OJ?
The multipolygon causes an error
the geometrycollection not.
Is this behaviour OGC-conform (simpel features...)?
What do you think?
uwe
Am 08.04.2013 16:36, schrieb Stefan Steiniger:
> Hi,
>
> so - well the situati
Hi,
so - well the situation is not so nice, as it should be valid. However,
the JTS TestBuilder says the Multi-Polgyon is invalid because of
"Self-intersection at or near point (175.0, 125.0, NaN)"
Same message appears when you try to add it as a new feature.
maybe you can make it valid before
Hi,
if you put a third geometrie to the two polygons,
for instance a linestring, and combine them
you will receive a geometrycollection
and not a multipolygon.
The geometrycollection causes *no* errors
but the multipolygon.
Uwe
Am 08.04.2013 12:05, schrieb Uwe Dalluege:
> Hi,
>
> I get the err
,
263 125,
175 125
)))
It cannot be added as WKT either.
-Jukka-
> -Alkuperäinen viesti-
> Lähettäjä: Uwe Dalluege [mailto:uwe.dallu...@hcu-hamburg.de]
> Lähetetty: 8. huhtikuuta 2013 13:06
> Vastaanottaja: Devel Jump
> Aihe: [JPP-Devel] The
Hi,
I get the error:
"The new geometry is invalid. Cancelled."
and I am not shure whether this error is correct.
1. Switch "Snap to vertices" option.
2. Draw a rectangle.
3. Draw a second rectangle with two identical
vertices from the first rectangle (with snap).
4. Select the two rectangles
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