I am trying to convert a dataset of lines that contains the coast of New Zealand into a big polygon.
However using the vector -> geometry tools -> lines to polygon command in Quantum GIS results in a mess with lots of holes and lines outside of the coast.
How can I do the conversion successfully?
It worked on the 1:500k data, the 1:250k data, but not the 1:50k data.
I have a screenshot of the problem here - before and after:
The dataset is from here.