[GIS] Smoothen Line vector QGIS

lineqgissmoothing

I am working on a publication and would like to make my schematic visually pleasing. The amount of detail is too high and the image would be better If I could simplify and smooth my line and polygon vectors. Ideally it would minic smooth Bezier like curves. (Curves are not yet supported in QGIS so searching an alternative)

I've tried many many settings in QGIS, primarily the v.generalize tool but I either get errors or the results still has sharp corners.

A close up reveals the ugly sharp corners of the vectors.

And I would like to get something like this:

Is there a simple way to simplify the vectors into smooth lines? Alternativily, which settings in GRASS v.generalize should I use?

It seems like v.generalize with Chaiken algorithm could do the trick. Searching for the correct settings. (Trial and error)

Shapefiles can be found here

Best Answer

You can use a geometry generator in styling as symbol layer style and smooth function. The advantage of this solution is that the geometry is intact.

Smooth 0:

Smooth 5:

Related Solutions

QGIS Bezier Curve Tool – Availability and Usage

As gene mentioned, there is a Spline plugin to digitize curves. Control is limited but it might be a start. Check the plugin settings and adjust the tolerance value to fit your layer CRS and resolution, especially if the CRS is EPSG:4326).

enter image description here

[GIS] How to reproduce Smoothing from Generalizer Plugin in v.generalizer in Processing Toolbar using QGIS

There is a difference in wording but I think the options from the Generalizer plugin exists in the v.generalizer interface. Using Google Translate (yes, not the best thing to use) for the Generalizer Homepage, we can find a description on each algorithms used and their corresponding parameters.

In terms of Hermite Spline Interpolation, the homepage tells us:

Threshold - Determines the distance between the created points.

Thightness - Factor determining the degree of bending of the resulting line.

Now looking at the Help section in v.generalizer, we can try and find those parameters mentioned above. For Threshold:

threshold=float
Maximal tolerance value <------ This is in the options.
Options: 0-1000000000

For Thightness:

Minimum angle between two consecutive segments in Hermite method <--- This is in the options.

Hermite

In terms of Chaiken's Algorithm, the homepage tells us:

Level - Determines the number of iterations of the algorithm.

Weight - Determines the shear rate, the bigger the fillets are closer to the line of nodes.

Now we look at the Help section in v.generalizer again. For Level:

Number of iterations <----- This is in the options.

For Weight:

betweeness_thresh - It denotes to what extent a line is in between the other lines in the network (unsure if this is the correct parameter!)

Chaiken

I could be wrong with this, in which case hopefully others can advise and/or re-edit this post.

Best Answer

Related Solutions

QGIS Bezier Curve Tool – Availability and Usage

[GIS] How to reproduce Smoothing from Generalizer Plugin in v.generalizer in Processing Toolbar using QGIS

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