Create Buffer but keep original Attribute table

Question

I want to create a buffer around a number of features. It is important for me to keep the attributes of the features in the new buffer.shp layer. When I try to write a new VectorLayer with a QgsVectorFileWriter, I do get the buffered polygons and also the fields of the original layer get copied over, however the attribute table stays empty.

How can I copy over the attributes of the original layer to the buffer layer?

As you can see I already tried to load the attributes using the . attributes() method on the QgsFeature object and setting the attributes. However I feel I am missing something here.

for f in feats:
 attributes = f.attributes()
 f.setAttributes(attributes)

See full code below:

path = '/Volumes/VAW_ETH-Z/M.Thesis/data/geospatial/'
# load filtered sgi
sgi_filtered = QgsVectorLayer(path + 'sgi_filtered.shp')
## Create buffer around filtered sgi
outFn = path + 'gl_buffer3.shp'
bufferDist = 50 # in map units
fields = sgi_filtered.fields()
feats = sgi_filtered.getFeatures()
writer = QgsVectorFileWriter(
 outFn,
 'utf-8',
 fields,
 QgsWkbTypes.Polygon,
 sgi_filtered.sourceCrs(), # loads the reference system of the source feature
 'ESRI Shapefile')
for f in feats:
 attributes = f.attributes()
 f.setAttributes(attributes)
 geom = f.geometry()
 buff = geom.buffer(bufferDist, 5)
 f.setGeometry(buff)
 
 writer.addFeature(f)

Screenshot of the Attribute Table below (it shows the fields but no attributes):

Empty Attribute table. The fields are displayed however no attributes have been added.

• Taras: Check this one: gis.stackexchange.com/questions/429034/…

Answer 1

Just add del writer after for loop.

for f in feats:
 attributes = f.attributes()
 f.setAttributes(attributes)
 geom = f.geometry()
 buff = geom.buffer(bufferDist, 5)
 f.setGeometry(buff)
 
 writer.addFeature(f)
del writer

• J.Beer: Oh thanks a lot! Can you tell me the reason why It is important to delete the writer?
• Kadir Şahbaz: You need to delete the writer to flush features to disk.