After successfully merging lines (using snapping) with merge_selected_features i got nice result - one merged line. Next thing was to make polygon from created merged line. Result is not nice - it creates multiple polygons connecting ends from separate lines which were merged previously together. Somehow merging geometry is not working for me or i am missing something.

.. Solved. I imported lines in Grass, then i used v.build.polylines and got nice line from which i was able to create correct polygon.

  • Instead of editing the title to include "Solved", please accept an answer. If there is no suitable answer, you can write one yourself. – underdark Aug 24 '12 at 9:35
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    got it. just didnt want to wait 8 hours ;) – Didzis Aug 24 '12 at 14:25
  • It should have worked. I have tested it in QGIS 1.8 in windows vista, and the merge_features --> Lines to Polygons sequence worked well. – Alexandre Neto Aug 24 '12 at 14:36

I should try using the Polygoniser plug-in. You shouldn't need to merge the lines to use this. See: http://confound.me.uk/maps/ppv4.pdf


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  • Testing right now. New version went to 55% and old version - to 95%; both didnt work, it freezed and stopped QGIS. – Didzis Aug 24 '12 at 8:50
  • Pleased to hear that you've got around the problem. For the record, to work the polygonizer plug-in needs the python-shapely package to be installed. N. – nhopton Aug 24 '12 at 9:05
  • will try with OSGeo4W. previously tried with installed QGIS version and i guess without that shapely lib. – Didzis Aug 24 '12 at 9:20

Isn't this a result of the lines being different directions? I believe it should work if all the joined lines are in the same direction & then reindexed so that the node numbers are in the proper sequence.

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