Re: [Anuga-user] About mesh generation

[Vinay E. <vin...@gm...>]

Hai Gareth,

Yes that problem has solved already, I am going further now

The problem was with the .csv file, In fact I should have kept the order
either clock wise or anti-clock while retrieving boundary points from GIS
or else I need serious investigation about intersection. anyway it works
now!

Many thanks for your help
Vinay

On Thu, Jun 9, 2016 at 3:48 PM, Gareth Davies <gar...@gm...>
wrote:

> Hi Vinay,
>
> The error message suggests that your polygon (in GEBCO_poly.csv) is
> self-intersecting. Is that correct? Maybe you can plot it and check.
>
> If it is, the I suggest you edit the coordinates in GEBCO_poly.csv to
> remove the self-intersection.
>
> Beware also that some GIS programs can make polygons with many extra
> points, and if they are extremely close to each other then ANUGA might
> think there is a self intersection due to round-off. I have seen some
> polygons that didn't appear to be self-intersecting, based on a casual
> plot, but on careful inspection were suffering from these issues.
>
> Cheers,
> Gareth
>
> On Thu, Jun 9, 2016 at 12:22 PM, Vinay Elothunkal <vin...@gm...>
> wrote:
>
>> Dear all,
>>
>> How can I handle the following error when generating a mesh that polygons
>> cross
>>
>> Traceback (most recent call last):
>>   File "runcairns_vinay.py", line 26, in <module>
>>     import project_vinay                 # Definition of file names and
>> polygons
>>   File "/data/anuga_flood/carins_vinay/project_vinay.py", line 43, in
>> <module>
>>     poly_GEBCO = anuga.read_polygon('GEBCO_poly.csv')
>>   File
>> "/usr/local/lib/python2.7/dist-packages/anuga/geometry/polygon.py", line
>> 852, in read_polygon
>>     raise Exception, msg
>> Exception: ERROR: Self-intersecting polygon detected in file
>> GEBCO_poly.csv. A complex polygon will not necessarily break the algorithms
>> within ANUGA, but itusually signifies pathological data. Please fix this
>> file
>>
>>
>> Thanks in advance,
>> Vinay
>>
>>
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>