[Qgis-user] Support - representing a graph in Qgis

[chris hermansen]

Giacomo and list,

On Wed, Feb 10, 2021 at 4:05 AM Giacomo Uguccioni <
giacomo.uguccioni at gmail.com> wrote:

> Thanks a lot!
> I would like to represent a shapefile or more shapefiles of nodes and
> connections (lines and points)
> in a layout similar to an electrical scheme, a symbolic and conceptual
> scheme and not a geographical one.
> I attached an image with qgis view and output that I would like to get.
>
>
In your graph representation (version to the right in your sketch) how do
you determine that A is the start node?  (and not 3 or 4?)

This kind of diagram is what Graphviz is built to represent.  You will need
to convert your shapefiles to a Graphviz input program.  A reasonable
starting approach might be to use some vector operations to get attribute
tables that look like [from-node,to-node] along with the node attributes.
I suggest you study the Graphviz documentation, which is quite excellent
and full of worked examples, to see how to draw the sketch you presented
here, and then revisit your shapefiles to think about how to convert them
to that format.


-- 
Chris Hermansen · clhermansen "at" gmail "dot" com

C'est ma façon de parler.
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