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

[Andrea Giudiceandrea]

Hi Andrew,
since I don't see any followups in the thread, I guess you have managed 
to find the root cause of the issue and to fix it.

If so, may you please let me know what was the root cause of the issue 
and how did you manage to fix it?

Best regards.

Andrea

Il 28/11/2024 20:39, Andrea Giudiceandrea ha scritto:
> 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