3

I am looking to automate the create of a fishnet grid over a large area (about the size of Rhode Island) for a mapping study. I want to use hexagonal grid cells, but the kicker is I need each of these hexagonal grids again broken down into their 6 hexants. The center convergent vertex will be a setup location with mapping done out to the extent of each hexant. Sort of like flying the petals from the pistil of a flower.

enter image description here

I don't see custom grid shapes in QGIS. I'm wondering how I can create this grid layout.

My first thought was to lay down hex grids and then do a series of layer copying with systematic offsets and a final merge to get what I need. Or to convert grids to polylines, copy those lines with the bearings I want, and repaste/offset those. But there's got to be other tools or a simpler process out there.

Improve this question

1 Answer 1

Reset to default
4

So, here is my suggestion, if I understood you correctly, proceed as follows,

i.e. it is a technique that can be automated:

Input data are hexagons fig. 1

enter image description here

  1. Vector>Processing geometry>Point extract;
  2. Data Analysis>Toolbar>General Vector>Erase the same geometry - this is important!
  3. Create centroids on the hexagon layer, copy them and paste them into the "Cleared Vertices" layer;
  4. Run Vector>Processing geometry>Triangulation Delaunay on the updated merged point layer "Clear Vertices"....
  5. Run Vector>Geo-processing>Crossing (results layer 4 and hexagon)

And you should get what you ask...fig. 2

enter image description here

Translated with www.DeepL.com/Translator (free version)

Improve this answer
10
  • Thanks for your response. I can't seem to find "Crossing". Is it called something else? And by "Erase the same geometry", you're referring to "delete duplicate geometries", correct?
    – BenW
    Sep 24, 2020 at 18:08
  • these are translation problems! 1) Maybe Intersection...2) "delete duplicate geometries" - yes, that's right...
    – Cyril Mikhalchenko
    Sep 24, 2020 at 18:15
  • Great thanks. Also I ran my delaunay triangulation on the de-duped vertices + centroids point layer, but this is the resulting triangles. It seems off. imgur.com/a/aw4bVXl.
    – BenW
    Sep 24, 2020 at 18:18
  • Hmmm. Yep that is what I used. Toolbox->Vector General->Delete Duplicate Geometries. Then pasted the centroids into that points layer. Then ran Delaunay. The results are the imgur screenshot. Reran, same results.
    – BenW
    Sep 24, 2020 at 18:33
  • 1
    Yes I used Vector>Research Tools>Create a Grid>Hexagons. I also found upon further inspection that there are some erroneous vertices generated and remaining even after removing duplicate geometry. Once I manually deleted those bad vertices of the process worked. Now to figure out why those erroneous extraneous vertices :-/ Thanks!
    – BenW
    Sep 24, 2020 at 19:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.