I've come across a problem using the geo-processing tools in QGIS and the extents of layers from PostGIS.
It seems like QGIS is using an estimated extent for a PostGIS layer which then leads to issues when using geo-processing tools (creating a TIN or Voronoi polygon set, for example). Loading the same dataset as a shapefile returns
an exact extent.
For a point dataset, for example, I get the following extents in QGIS and PostGIS:
The PostGIS estimated extent matches the QGIS estimated extent and is smaller than the exact extent. The shapefile exact extent matches the PostGIS exact extent. In this case the estimated extent is 91% of the exact extent which is somewhat sub-optimal...
I’m running QGIS 2.6, 2.8.3 and 2.10.1 with PostgreSQL 9.2.13 and PostGIS 2.1.8 on Windows 7 32bit.
I have tried with my PostGIS connection set with and without the “use estimated metadata” and have updated the table statistics in the database with VACUUM ANALYSE but still get the same results. I imagine
the estimated extents make things a bit faster.
This message is strictly confidential. If you have received
this in error, please inform the sender and remove it from your system. If received in error you may not copy, print, forward or use it or any attachment in any way. This message is not capable of creating a legal contract or a binding representation and does
not represent the views of Angus Council. Emails may be monitored for security and network management reasons.Messages containing inappropriate content may be intercepted. Angus Council does not accept any liability for any harm that may be caused to the recipient system or data on it by this message or any attachment.