Feature request #19943
Extend algorithm only extends, but does not shorten lines
|Pull Request or Patch supplied:||No||Resolution:||wontfix|
|Easy fix?:||No||Copied to github as #:||27765|
Currently, there is an algorithm called Extend lines (visit documentation: https://docs.qgis.org/testing/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#extend-lines) which work great for extending lines, but I haven't been able to use it for reducing a line's length.
Provided a line with
If I use the following values:
start distance = 2,
end distance = 2, I get a new line with
If, on the contrary, I use negative values (
start distance = -2,
end distance = -2), I do not get a new line with
5-2-2) as expected, but I get a line with the same length as the original one.
#6 Updated by Carlos Cámara over 2 years ago
I am using 3.2.3 and I can't find such
line substring algorithm. I haven't found any reference on documentation, neither.
Since I have not used it, I am not sure how that algorithm works, but I would suggest reconsidering reopening this issue as a feature request if it does not work like that:
Imagine that I want to change the length of a line according to a field, which may be positive (extend) or negative (shrink). IMHO it would be great to solve this by using a single tool, not two different ones. I am not a programmer at all, but I cannot see any difference in changing a line's length while keeping its direction, no matter if that length is positive or negative.