polyline-creationqgisqgis-processing
I have a set of points which I would like to change into a polygon.
I tried concave hull but do not get the intended polygon as you can see below,
And when I use Denaulay Triangulation I need to delete the outer triangles.
Is there an efficient way of doing the same?
I also tried Convex hull.
There is a concave hull option in QGIS but it's available in the Processing toolbox only; it only works on points, so you have to extract nodes before you run it.
This can be done more easily using a model, without the need to save intermediate sets of nodes:
Models|Tools|Create new model.
To run, add a set of points, lines or polygons, then double-click the model and run it on your layer:
You want the concave hull or Alpha shape ?
You have many solutions (Python only, R, GRASS GIS, OpenJump,...) and in QGIS
qgis:concavehull (Concave Hull)r:alphashape (with the R packages alphahull)And with a buffer, as AndreJ says
Best Answer
I assume that you know which points belong to the "left" or "right", because otherwise there are many solutions. If so, you could use the delaunay triangulation followed with a selection of the "central" triangles. With this method, no need to have the points in a specific order. All you need to consider is the fact that the triangles you need must touch at least one point from each side.