Hallo Andrea

Excuse me for disturbing you again with the same topic.

We still have problem with polygon definition.
I'm trying to ask you again, if my polygon consist of one inner linear ring and 
one outer liner ring and the two rings touch each other in one single point, I 
get a exception, but I cannot read find in specification why not allow this 
situation.

See my picture.

Please let me know this situation is allowed or not.

Thanks in advance

Balazs

+----------+----------+
|         / \         |
|        /   \        |
|       /     \       |
|      +-------+      |
|       inner ring    |
|                     |
+---------------------+
  Outer ring


-----Ursprüngliche Nachricht-----
Von: Andrea Aime [mailto:[EMAIL PROTECTED] 
Gesendet: Dienstag, 28. November 2006 20:39
An: Ian Turton
Cc: Szakacs, Balazs; [email protected]
Betreff: Re: [Geotools-gt2-users] may touch a inner and outer rings ?

Ian Turton ha scritto:
> On 11/28/06, Szakacs, Balazs <[EMAIL PROTECTED]> wrote:
> 
>> If I'm trying to insert a multi polygon but I get an exception:
>> java.lang.IllegalArgumentException: geometries must not
>> contain null elements at .....
>>
>>
>>
>> It's happened only if the inner boundary linear ring touches the outer
>> boundary ring. I didn't find anything in GML document about the common point
>> of inner and outer rings.
> 
> That's definitely not allowed in which ever spec it is that defines
> Polygons - I forget which spec JTS (and thus GeoTools) implements for
> geometry.

Simple feature specification 1.1, and yes, if it's a single point, you
can represent the same geometry with a single outer loop, whilst
if it's multiple points, you can represent the same as a multipolygon
(two or more polygons touching) (see page 2-9 in the spec).

Cheers
Andrea Aime

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