Bug report #15487
"Create single-part geometries instead of multi-part" option broken
Status: | Closed | ||
---|---|---|---|
Priority: | Normal | ||
Assignee: | |||
Category: | DB Manager | ||
Affected QGIS version: | 2.16.1 | Regression?: | No |
Operating System: | Easy fix?: | No | |
Pull Request or Patch supplied: | No | Resolution: | invalid |
Crashes QGIS or corrupts data: | No | Copied to github as #: | 23411 |
Description
When importing multi-part geometries the "Create single-part geometries instead of multi-part" option throws an error:
Error 7
Feature write errors:
Creation error for features from #0 to #0. Provider errors was:
PostGIS error while adding features: FEHLER: Geometry type (MultiPolygon) does not match column type (Polygon)
History
#1
Updated by Tudor Bărăscu almost 8 years ago
I also just encountered this issue.
Steps to reproduce:
- Download natural earth coutntries data (http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/10m/cultural/ne_10m_admin_0_countries.zip
and try to import as simple features (as multipart it works)
If you try the sqlite file http://naciscdn.org/naturalearth/packages/natural_earth_vector.sqlite.zip it won't work for either options (create as simple or as multipart features)
- The error is the same
#2
Updated by Sandro Santilli almost 8 years ago
- Status changed from Open to Feedback
- Assignee set to Sandro Santilli
The shapefile contains record with multi-geometries, what would you expect from the "Create single-part geometries instead of multi-part" option ?
The option is passed to QgsVectorLayerImport which does not document the semantic of that option ("forceSinglePartGeometryType").
Also, why is this marked as Severe/Regression ?
#3
Updated by R. R. almost 8 years ago
As far as I remember former QGIS versions have converted the multipart geometries into singlepart geometries instead of throwing an error. I'll test this later.
#4
Updated by Sandro Santilli almost 8 years ago
Reinhard let me know what you find, and what does it mean to "convert a multipart into singlepart" (augmenting the number of records ? picking just the first component ?)
#5
Updated by R. R. almost 8 years ago
I must have been wrong, since QGIS 2.8.1 throws the same error. To me, 'Create single-part geometries instead of multi-part' in the DB-Manager should work in the same way as 'Multipart to singleparts' in the processing toolbox.
#6
Updated by Sandro Santilli almost 8 years ago
- Priority changed from Severe/Regression to Normal
How does "Multipart to singleparts" work, within processing ? (downgrading from Severe/Regression to Normal)
#7
Updated by R. R. almost 8 years ago
'Multipart to singleparts' converts a multipart feature with 'n' geometries to 'n' singlepart features.
#8
Updated by Sandro Santilli almost 8 years ago
I don't think "Create single-part geometries instead of multi-part" was ever meant to apply any conversion.
The "Import vector to PostGIS" processing tool might be closer, having a "Promote to multipart" switch.
Can you please try how that processing tools behave if you uncheck the "Promote to multipart" setting ?
#9
Updated by Giovanni Manghi over 7 years ago
- Resolution set to invalid
- Status changed from Feedback to Closed
Sandro Santilli wrote:
I don't think "Create single-part geometries instead of multi-part" was ever meant to apply any conversion.
That is correct. The wording is somehow misleading, but the option work as expected:
- by default any vector is imported into a MULTI* table even if the input layer has no multipart geometries
- if the input layer has no multipart geometries then this option allows to import it into a POINT/LINESTRING/POLYGON table (not MULTI*)
- if the input layer has multipart geometries than the option cannot be used and will return the described error