some features dissapear when zooming in beyond certain scale when the datasource is in a network drive

[reginaldc]

Describe the bug

How to Reproduce

QGIS and OS versions

Additional context

Hi,

In our organisation we use a shapefile containing 234 features that is located on a network drive.
We use QGIS 3.8.3 (osgeo installation)
Lately we observe that some features dissapeared. They are still in the attribute table. When you click on zoom to feature you don't see the feature. When you choose for flash then the polygon flashes. When you zoom out beyond 1:10000 the feature is suddenly visible again. This doesn't happen for most other features from the layer, so it is not a matter of settings in the rendering.
When I copy the dbf, shp , shx and prj files of the shape to my C drive all features show up correctly. So I assume that it has something to do with the network drive.

Regards,

[andreasneumann]

Interesting, I observed the same with Geopackage layers. Mainly after editing features (e.g. cutting polygons apart or merging them).

My vague assumption is that the data is still there, but the bounding boxes of the feature might be broken or not taken into account in some scales.

Did you edit the features in your shapefile?

This is really something that should be fixed before the release.

I will try to investigate more - but I am pretty sure, that this not related to Shapefiles only, but vector features in general, as I had the same thing with Geopackage files.

[andreasneumann]

BTW - in my case the Geopackage was local - not on a network drive.

[andreasneumann]

Hm - currently I can't reproduce it at all on my other machine. I will have to check with my other machine where I observed the behaviour. Maybe it is related to different GDAL/GEOS versions?

Will investigate more on this.

[reginaldc]

Hi Andreas,

I did remove some fields from the shapefile before I noticed the dissappearing features. It could be that the removing of the fields has nothing to do with the features dissapearing.

[nyalldawson]

This is usually caused by a corrupt spatial index in the file. Removing and rebuilding it should fix the issue

[reginaldc]

Building a spatial index solved the problem