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How to use notify to automatically refresh layers in QGIS?
This was developed by the wizards from Oslandia and is easily added to any existing table in your PostgreSQL database – including PostGIS tables. This feature was added in version 3.0 (see https://qgis.org/en/site/forusers/visualchangelog30/#feature-trigger-layer-refresh-or-layer-actions-from-postgresql-notify-signal ).
Why does refresh not work in QGIS 2.6?
The API warns that both QgsMapLayer.setCacheImage () and QgsMapLayer.clearCacheImage () are deprecated, but nothing in the documentation or code mentions what alternative is planned. Side note: I’m still seeing a refresh bug.
How to make QGIS layer update from changed data source?
Or maybe I did something two minutes ago. The one reproducible way of getting it to update is to duplicate the layer from the legend menu – the duplicate always gets its data from the current shapefile, and the original layer updates itself too! So there must be some way of doing it.
How to force QGIS to reopen a file?
Unfortunately there is no API to nicely force QGIS to reopen the file in QGIS 2.10. As a workaround you can use an ugly hack: I just introduced a new method which will be available starting from QGIS 2.12:
How are output raster files chosen in virtual raster?
By default the average resolution of th raster files will be chosen. With ‘False’ you can define that each raster file goes into a separated stacked band in the VRT band. Allows that the output bands have different projections derived from the projection of the input raster layers. Output raster file.
How to create multiple maps in QGIS document?
QGIS allows you to create multiple maps using the same map file. reason, it has a tool called the Layout Manager. Click on the Project ‣ Layout Managermenu entry to open You’ll see a blank Layout managerdialog appear.
Where do I save the layout in QGIS?
Layoutin QGIS is part of the main map file, you’ll need to save your main project. Go to the main QGIS window (the one with the Layerspanel and all the other familiar elements you were working with before), and save your project from there as usual.
How to refresh all materialized views in PostgreSQL?
Unfortunately, there is currently no PostgreSQL command to refresh all views in the proper order. I therefore created a couple of simple views that use recursion on system tables to determine the hierarchy of views and materialized views, which can then be used to refresh those materialized views in the correct order.
What does the update SQL layer option do in QGIS?
What does the Update SQL Layer option do in QGIS? The Update SQL Layer option is available when you right click on a Layer in the Layers Panel, but only when the Layer Source is within a Spatial Database e.g. PostGIS.
How is a SQL filter applied in QGIS?
Once the Layer is Updated the SQL filter is applied to the Layer in QGIS and now only the Planning Apps where the Progress value = ‘Passed’ are shown. There is also a Query Builder tool which enables you to construct more complex queries and to apply Column filters very easily.