[Qgis-user] Drop the points and show only clusters
Andrea Giudiceandrea
andreaerdna at libero.it
Mon Jan 31 02:55:00 PST 2022
> Simon Dietmann
> <https://www.mail-archive.com/search?l=qgis-user@lists.osgeo.org&q=from:%22Simon+Dietmann%22>Mon,
> 31 Jan 2022 00:07:19 -0800
> <https://www.mail-archive.com/search?l=qgis-user@lists.osgeo.org&q=date:20220131>
>
> the reason für all the ‘1’ values is obviously that the algorithm seeking for
> the nearest points always finds the original point itself. When I first used
> the expression that I had suggested as a solution for your problem, this didn´t
> happen and the original point wasn´t taken into accont, but when I later tried
> it with another point layer, I got the same result as you with ‘1’ for every
> point feature.
Hi Simon,
as I've written in a previous message, I think a bug occurs when the
overlay_nearest function is used with a Shapefile layer, while the bug
doesn't occur with a Memory or GeoPackage or Spatialite layer.
Could you please try this:
- create a new scratch (Memory) point layer
- add a single point to the memory layer
- use the expression overlay_nearest(@layer,$geometry) in the field
calculator for such layer: the preview will show [] (i.e. no nearest
geometry returned)
- export the memory layer with a single point to a Shapefile layer
- import the Shapefile layer with a single point
- use the expression overlay_nearest(@layer,$geometry) in the field
calculator for such layer: the preview will show [ <geometry: Point> ]
(i.e. the expression incorrectly returns the very some point as the
nearest point)
- export the memory layer with a single point to a GeoPackage or a
Spatialite layer
- import the GeoPackage or a Spatialite layer with a single point
- use the expression overlay_nearest(@layer,$geometry) in the field
calculator for such layer: the preview will show [] (i.e. no nearest
geometry returned)
Best regards.
Andrea Giudiceandrea
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