[Qgis-user] Center line of an elongated BASIN

[Zoltan]

Hi,
I'm coming in late to this methodology discussion, so apologies if I am 
off the mark.

So by 'center line' I'm guessing you mean a line that is always 
equidistant from the polygon boundary.

I had a similar problem a few years back where I had to create road 
center lines from a polygon road representation for a small country.

After some experimentation on speed and efficacy, I came up with a 
Python script that:

    merged (dissolved) all poygons) - but you only have 1 polygon :-)
    rasterised the polygon (as finely as you choose relevant to your issue)
    ran r.thin
    vectorised the (now) single line of cells.
    ran a Douglas-Peuker style smoothing on the staircase lines

Worked like a dream for my purpose.
Maybe you could adapt this logic flow to your needs?

HTH,
Zoltan

On 2022-02-11 00:46, Allan López wrote:
> Yes, it does.
>
> Thanks a lot indeed. I am testing it.
>
> Best,
>
> Allan
>
> El jue, 10 feb 2022 a la(s) 15:19, Alexis R.L. (alroyliz0 at gmail.com) 
> escribió:
>
>     As far as I know v.voronoi.skeleton in gdal is the closest thing
>     we have that can do this in base QGIS.
>
>     I hope this helps,
>
>     Alex
>
>     Le mer. 9 févr. 2022 à 17:57, Allan López <allosa01 at gmail.com> a
>     écrit :
>
>         Dear All, I need to calculate and display the center line of
>         an elongated river basin ( not the center of the main river
>         trunk) from a SHP.
>
>         Thank's in advance.
>
>         Allan Lopez
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-- 

=============================================
Zoltan Szecsei GPrGISc 0031
Director, Geograph (Pty) Ltd.
GIS and Photogrammetric Services

Cape Town, South Africa.

Mobile: +27-83-6004028 (Signal, not WhatsApp)
www.geograph.co.za
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