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I work with QGIS, v. 2.0.1. I have a point layer in which I have structures that could be represented as lines or polygons, but at the moment they are represented as a group of points. I know I can create new layers with different geometry but if I do this, I don't have the attribute table of the original point layer attached to the new line/polygon layer. And if I copy the point layer, I have the attribute table but it's not the right geometry. Can I change the geometry afterwards?

I could do a table join, right? But I don't have a common attribute and the table join is not permanent is it?

I tried the "PointstoPaths" Plugin, but it's not what I'm looking for. I also found the "Points2One" Plugin which seems perfect for my problem, but somehow it doesn't work (a shapefile is created but I can't "see" anything in the map).

That's how the map looks: for lines:

enter image description here

and for polygons:

enter image description here

I have about 800 points and the attributes show name of the place, measurements, date and much more.

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    The key problem you are describing seems to be that you don't have a "common attribute". If that is the case then you can only really associate the points by proximity (closeness or a specified distance). Or associate them manually. Expand on your question with more information about your data, how many points, what info is in the attributes. Also see this for a similar problem gis.stackexchange.com/questions/89122/… Commented Mar 17, 2014 at 9:20
  • Does this help? ... gis.stackexchange.com/questions/224025/… Commented Jan 23, 2017 at 4:12

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Creating a buffer around points (or lines) will result in a polygon shapefile that preserves the attribute table.

If you want to connect your points to a line or polygon, you have to specify the sequence of the points in the line. Form your images, I have not understood how you want to do this.

If you want to join 2 points with different attributes, only one can be stored for the line.

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  • I just want to connect some points to a line/polygon but not all of them. For example in the first image, I want to represent the river as a line, not as many points, in the second image I want to have a polygon but at the moment I have some points that are the outline of the polygon. Can I create a buffer around a selection of points? I tried to create one but it only works for all points. Commented Mar 17, 2014 at 13:17
  • You can select points by rectangle, and click to buffer only selected. Or you add a column in the attribute table, give the river points a certain value, and filter the layer by that. Commented Mar 17, 2014 at 13:47
  • Ok the buffer thing is not working. What do you mean with filter the layer by that? I actually want a result like this: i.sstatic.net/DfdKI.png But as you can see I have two layers. The point layer has the complete attribute table and the polygon layer has just one value. Can I do something that they share the attribute table? Commented Mar 17, 2014 at 15:07
  • If your data is in degrees, you have to set a very small value for buffering. For the filter, Rightclick on the layer entry, -> Filter lets you choose a field and a value, like "name"='xyz'. Only matching features will be displayed with that, and the buffer will also be only around those points. Commented Mar 18, 2014 at 12:00
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For as few as 800 points and if you don't expect to be doing this anytime again soon, I would do it manually. Look in settings and turn snapping on with minimum tolerance, digitise a new line on the points. It'll be a lot more achievable.

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