Bug report #21993
ST_Buffer does not work with postgis layer
| Status: | Closed | ||
|---|---|---|---|
| Priority: | Normal | ||
| Assignee: | - | ||
| Category: | Data Provider/PostGIS | ||
| Affected QGIS version: | 3.6.2 | Regression?: | No |
| Operating System: | windows 7 | Easy fix?: | No |
| Pull Request or Patch supplied: | No | Resolution: | invalid |
| Crashes QGIS or corrupts data: | No | Copied to github as #: | 29808 |
Description
I have a postgis table with a geometry column containg a linestring of SRID 3035. I can't get a buffer created using ST_Buffer to work.
When I use this SQL statement:
SELECT ST_Buffer(geom, 20)), id from erhaltung.abschnitt and set the unique-values column and geography column accordingly, I receive the warrning message
Feature type or srid for st_buffer of (SELECT ST_Buffer(geometrie, 20), id from erhaltung.abschnitt
) AS "subQuery_0" could not be determined or was not requested.
and the attribute table for the layer is empty.
When I use
SELECT ST_AsEWKT(ST_Buffer(geometrie, 20)), id from erhaltung.abschnitt
the preview of the data in the update sql layer dialog looks correct for the geometry:
st_asewkt id
SRID=3035;POLYGON) 26
and the features show up in the attribute table, but the features show up in a completely wrong place (some place in Saudi Arabia instead of Germany).
History
#1
Updated by Giovanni Manghi almost 5 years ago
- Status changed from Open to Feedback
can you attach a dump of your table?
#2
Updated by Sebastian Brocks almost 5 years ago
- File abschnitt.sql added
- Status changed from Feedback to Open
Here's a dump of the table.
#3
Updated by Giovanni Manghi almost 5 years ago
- Status changed from Open to Closed
- Resolution set to invalid
Sebastian Brocks wrote:
Here's a dump of the table.
the correct query for your data is
SELECT ST_Buffer(geometrie, 20), id from erhaltung.abschnitt
#4
Updated by Sebastian Brocks almost 5 years ago
- Status changed from Closed to Reopened
I tried that, and it didn't work. As I said earlier, with that query, the attribute table is empty and I get this warning in the General Log:
Feature type or srid for st_buffer of (SELECT ST_Buffer(geometrie, 20), id from erhaltung.abschnitt ) AS "subQuery_0" could not be determined or was not requested.
#5
Updated by Giovanni Manghi almost 5 years ago
- Status changed from Reopened to Feedback
Sebastian Brocks wrote:
I tried that, and it didn't work. As I said earlier, with that query, the attribute table is empty and I get this warning in the General Log:
Feature type or srid for st_buffer of (SELECT ST_Buffer(geometrie, 20), id from erhaltung.abschnitt ) AS "subQuery_0" could not be determined or was not requested.
it works perfectly fine here, with your data.
#6
Updated by Sebastian Brocks almost 5 years ago
Ok, it seems the problem was that because I buffered a linear layer, I had to manually change the type of the layer from Line and LineString to Polygon. After doing that by editing the project file, I got it to work. Is there any way to do that automatically?
#7
Updated by Giovanni Manghi almost 5 years ago
Sebastian Brocks wrote:
Ok, it seems the problem was that because I buffered a linear layer, I had to manually change the type of the layer from Line and LineString to Polygon. After doing that by editing the project file, I got it to work. Is there any way to do that automatically?
I don't follow, I didn't had to do that to load the results of the above query in the project, I just run the query in DB Manager and loaded the results as query layer.
#8
Updated by Sebastian Brocks almost 5 years ago
Ah, I hadn't found the option to run a query directly without first adding a layer. Thanks for the info!
#9
Updated by Giovanni Manghi almost 5 years ago
Sebastian Brocks wrote:
Ah, I hadn't found the option to run a query directly without first adding a layer. Thanks for the info!
so can we close this?
#10
Updated by Sebastian Brocks almost 5 years ago
Yes.
#11
Updated by Giovanni Manghi almost 5 years ago
- Status changed from Feedback to Closed