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I created a grid of hexagons and kept only the hexagons in a circle. In effect many hexagon-ids are missing and the remaining ones start at 1409.

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I want them to be numbered consecutively in a logic way starting with 1 (top to bottom, left to right); i. e. 1409 should be 1, 1410 should be 2 ... 1495 should be 9, 1496 should be 10 ...

The attempt to use the expression @row_number in the field calculator as suggested by this post: Filling column with consecutive numbers in QGIS used the Feature ID + 1 for the new value, as can be seen in the column 'test'.

enter image description here

From the list of functions (https://docs.qgis.org/testing/en/docs/user_manual/expressions/functions_list.html#functions-list) I understand that it should take the row-number instead, which would result in the exact sequence I desire.

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  • Not an answer but there is a sort and number plugin which you could use instead.
    – John
    Commented Dec 30, 2022 at 18:13
  • After deleting the features, did you toggle edit mode to save the changes? If not, no wonder @row_number returns the same value
    – Babel
    Commented Dec 30, 2022 at 19:02
  • @John Thank you very much, I use the "sort and number"-plugin as a workaraound. Still not the neatest solution, but it does the job.
    – SAM
    Commented Dec 30, 2022 at 19:49
  • Babel: I exported the selected hexagons as a seperate shape-file, so saving should not be a problem, I also closed and reopened QGIS many times. Also the row-numbers started with 1, so it is not that the original rows have been used, as the original hexagon 1 has been deleted. Instead I received a consecutive series of numbers 1 to 5966, just as I wanted, only their placing was weird with 1 somewhere in the middle at the bottom. At the original grid, the 1 was in the upper left corner, which I cut off. With a rectangular grid as the original one, the expression @row_number works fine btw.
    – SAM
    Commented Dec 30, 2022 at 20:01
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    I can't reproduce the behivour you describe, when using @row_number, I get an increasing no. starting with 1, see screenshot: i.sstatic.net/cFFNp.jpg Can you provide/share the exported shapefile?
    – Babel
    Commented Dec 30, 2022 at 21:01

1 Answer 1

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It turns out to work just fine, if I save every step as a shape-file. Originally I always used the original grid as a temporary scratch layer and saved only the selected hexagons which form a circle. This created the error. So just make sure to save every step as a shape-file, it is worth the effort. Many thanks to Babel https://gis.stackexchange.com/users/88814/babel for forcing me to rethink the process.

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