[gdal-dev] Is it possible to add new fields to a shapefile and populate then?

[Stephen Woodbridge]

Rutger,

Thanks, that did the trick.

-Steve

On 4/4/2017 6:15 AM, Rutger wrote:
> Stephen Woodbridge wrote
>> On 4/3/2017 11:37 PM, jratike80 wrote:
>>> Stephen Woodbridge wrote
>>
>> Hi Jukka,
>>
>> Ahh, good point, I always seem to forget that fact.
>> I have gotten the python code to add the new fields, but the data is not
>> getting written to the file.
>>
>>      # open the shapefile
>>      driver = ogr.GetDriverByName('ESRI Shapefile')
>>      dataSource = driver.Open(infile, 1) # open for rw
>>      if dataSource is None:
>>          print "ERROR: could not open '%s' as shapefile!" % (infile)
>>          sys.exit(1)
>>
>>      layer = dataSource.GetLayer()
>>      layer.CreateField(ogr.FieldDefn("area",     ogr.OFTReal))
>>
>>
>>      for feature in layer:
>>          geom = feature.GetGeometryRef()
>>          feature.SetField("area", geom.GetArea())
>>          feature = None
>>
>>      dataSource = None
>>
>> In the cookbook example for "Create a New Shapefile and Add Data" there
>> is a call to:
>>
>> layer.CreateFeature(feature)
>>
>> but I do not see an equivalent call for:
>>
>> layer.UpdateFeature(feature)
>>
>> So How do I update the feature and force the data to get written to the
>> shapefile. I'm presuming the CreateFeature will append a new record
>> which is not what I want.
>>
>> -Steve
>>
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>
> Hey Stephen,
>
> I think you looking for "layer.SetFeature(feature)", which you can add right
> before destroying the changed feature object withing your loop.
>
>
> Regards,
> Rutger
>
>
>
>
> --
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