[FWTools] Starting with FWTool

[Bryan Keith]

> Hi,
>
>  Thanks for the help. I am trying to do the following:
>
> map = ogr.Open( str, update = 0 )
>
> where str holds the complete path but
>
> I get the following error:
>
> Traceback (most recent call last):
>   File "C:\Python24\My Programs\GISI.py", line 39, in
> OnOpen
>     x.f(dialog.GetPath())
>   File "C:\Python24\My Programs\GISI.py", line 7, in f
>     map = ogr.Open( str, update = 0 )
>   File "C:\Python24\Lib\site-packages\osgeo\ogr.py",
> line 3092, in Open
>     return _ogr.Open(*args, **kwargs)
> TypeError: in method 'Open', argument 1 of type 'char
> const *'
>
> If i hard code the file path liek
> c:\something\somthing\.... then it works fine.
> Can anyone tell me why the ogr.open doesnt like
> variable holding a string as parameter.

Faizan,

When creating the string, are you escaping the backslashes correctly?  I
think it should be:

str = 'c:\\something\\somthing\\....'

or

str = r'c:\something\somthing\....'

Bryan

>
> --- Frank Warmerdam <warmerdam at pobox.com> wrote:
>
>> Faizan Tayyab wrote:
>> > Hi,
>> >
>> >  Can anyone provide me with python code (OGR) for
>> > reading the geometry of a polygon shapefile. I am
>> able
>> > to obtain the geomerty reference but am unsure how
>> to
>> > read the geometry. I am planning to use matplotlib
>> to
>> > visualize the geometry.
>> >
>> > Anyone already done this????
>>
>> Faizan,
>>
>> I'm not aware of a direct example, but:
>>
>>
>>
> http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/vec_tr.py
>>
>> has logic to walk through any kind of geometry that
>> might be helpful.
>>
>> Basically, a polygon geometry will consist of a top
>> level object that
>> contains one or more rings accessed using
>> geom.GetGeometryRef().  Each
>> ring will contain 3 or more points accessed using
>> GetX(), and GetY().
>>
>> Best regards,
>> --
>>
> ---------------------------------------+--------------------------------------
>> I set the clouds in motion - turn up   | Frank
>> Warmerdam, warmerdam at pobox.com
>> light and sound - activate the windows |
>> http://pobox.com/~warmerdam
>> and watch the world go round - Rush    | President
>> OSGeo, http://osgeo.org
>>
>>
>
>
>
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