I am constructing a geological map which involves constructing boundaries to areas which vary in style across their length depending on how well defined they. To do this I have created two distinct layers called "certain" and "inferred", one solid the other dashed. I wish to automatically create a polygon fill surrounded by the boundaries, but when I use the lines -> polygon tool, I am only given the option to select one layer at a time.

Can I join the two layers together into one but retaining the changing style?

Alternatively, can I possibly change the style of the line within one layer, or can each layer only have one style?

  • 1
    Each layer can only have one style -> each style can have multiple symbol items. Therefore, you can have one solid line and one dashed line in a single layer. Just change the Single Symbol setting to another such as Categorized or Rule-based etc and in the symbol options (double-click on a symbol), add a new symbol item (green plus sign) and play around with the settings.
    – Joseph
    Oct 21 '15 at 15:30
  • Thanks @Joseph this is great for what I wanted with the lines. Unfortunately however the default 'lines -> polygon' algorithm cannot cope with the fact that the enclosed area is made up of seperate features, despite their intersection. From my searching it looks like the 'Polygonize' plugin would be helpful here, but I cannot find it on the plugins list, do you know how to get hold of it?
    – AlexLipp
    Oct 21 '15 at 15:53

I have worked out how to do this!

Using the Categorized line styles I generated multiple different styles for bits of the line. I then constructed joined up lines (using snapping tool to make sure they overlapped) which created closed shapes. I then ran the polygonize tool like so:

"Processing -> Commander" and then typing 'Polygonize' and following the instructions.


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