When I digitize a polygon and snap to existing features, sometimes the coordinates end up very slightly away from where I want them to be for example 15.000000099, rather than 16.
Is there a way to round each vertex to a fixed precision?
2 Answers
THIS WILL OVERWRITE YOUR DATA (MAKE A COPY)
That's easy:
- Open
Field Calculator. - Insert this code:
geom_from_wkt(geom_to_wkt(@geometry, 0)) - Replace
0with precision you need. - Check box
Update existing field. - Choose
<geometry>as a field. - Press
OK.
-parameters ---->before ------->after
Another example with point:
P.S. This can collapse your polygons to a point or line, so choose precision wisely.
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1Great answer -didn't know about the possibility to update geometries with field calculator! Do you know since which version this is possible?– BabelCommented Aug 20 at 12:59
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1@Babel This feature was implemented in 2016.
Changelog for QGIS 2.14 2016-02-26: qgis.org/project/visual-changelogs/visualchangelog214/… Commented Aug 20 at 19:22 -
Thanks for this. I will revert and accept once I have tested it. Commented Aug 21 at 0:27
You can use the "Snap points to grid" (native:snappointstogrid) processing algorithm https://docs.qgis.org/3.34/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#snap-points-to-grid
answered Aug 20 at 11:30
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As with all ways to do this in QGIS at the moment, this can lead to invalid geometries. If you want to have this solved, please "vote" on this QGIS issue :-): github.com/qgis/QGIS/issues/58023– PieterCommented Aug 20 at 15:56
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I will try this. However, the polygons were digitised by snapping to a generated grid of points at regular spacing, so I was surprised to find that some of the vertices were not exact when I extracted them. That is what I am trying to remedy. Commented Aug 21 at 0:26
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@LeighBettenay, I didn't understand correctly your question. May you please better clarify the issue? Commented Aug 21 at 5:43
15):for example 15.000000099, rather than 16.