[Qgis-user] Shapefile symbology no longer working when zoom in

[Andrea Giudiceandrea]

Hi Andrew,
are you actually using QGIS 3.34.0 or QGIS 3.40.0? If the former, 
firstly I suggest you to use QGIS 3.34.12, instead. What is the GDAL/OGR 
library version used by QGIS on your system?

> Andrew Chapman andrew.chapman at donkagen.co.uk
> Thu Nov 28 05:38:02 PST 2024
> I've tried Vector->Geometry Tools->Check Validity but the problem still
> exists
The "Check Validity" processing algorithm [1] doesn't fix any issue. You 
can use it e.g. to export only valid geometries from the affected layer. 
Does the issue occur also with the "Valid output" layer? Does the issue 
occur also if you just export the ESRI Shapefile layer to a new ESRI 
Shapefile layer or to a new GeoPackage layer and use the new layer?

In order to try to actually fix invalid geometries, you can use the "Fix 
geometries" processing algorithm [2].


> Andrew Chapman andrew.chapman at donkagen.co.uk
> Thu Nov 28 10:21:40 PST 2024
> In the layer properties->source tab if I delete the .shx file the option Create Spatial Index is grey’d out.  If the .shx file exists the same button is marked Spatial Index Exists and is again grey’d out.

AFAIK the correct way to create or recreate / fix the .shx file is to 
use the "Repair Shapefile" processing algorithm [3].

Anyway an .shx file doesn't actually contain a spatial index. According 
to "ESRI Shapefile / DBF" page [4], the ESRI Shapefile OGR driver can 
read and write the non-ESRI quadtree spatial index file (.qix ) and can 
read the ESRI spatial index file (.sbn / .sbx).

What are the extensions of all the affected ESRI Shapefile layer's files?

May you please provide the affected ESRI Shapefile layer's files or 
create an issue report on the QGIS GitHub repository [5] providing the 
affected layer?

Best reagards.

Andrea

[1] 
https://docs.qgis.org/3.34/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#check-validity
[2] 
https://docs.qgis.org/3.34/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#fix-geometries
[3] 
https://docs.qgis.org/3.34/en/docs/user_manual/processing_algs/qgis/vectorgeneral.html#repair-shapefile
[4] 
https://gdal.org/en/latest/drivers/vector/shapefile.html#spatial-and-attribute-indexing
[5] https://github.com/qgis/QGIS/issues