[Qgis-user] Save scratch layer vs. vector layer

[Andrea Giudiceandrea]

> Weig, Alfons A.Weig at uni-bayreuth.de
> Tue Mar 21 05:36:33 PDT 2023
> There are two possibilities to save the new layer, and I am not sure whether there is a fundamental difference between these two procedures:

Hi Alfons,
have you read the QGIS User Manual/Guide [1]? There it is explained that:

***
To avoid data loss when closing a project with temporary scratch layers, 
you can save these layers to any vector format supported by QGIS:

clicking the Memory indicator icon next to the layer;

selecting the Make permanent entry in the layer contextual menu;

using the Export ► entry from the contextual menu or the Layer ► Save 
As… menu.

Each of these commands opens the Save Vector Layer as dialog described 
in the Creating new layers from an existing layer section and the saved 
file replaces the temporary one in the Layers panel.
***

To add more info: the dialog window that is showed after clicking the 
(Memory) icon next to the layer or selecting the Make permanent entry in 
the layer contextual menu and the one that is showed after selecting the 
Export ► Save Features As… entry from the contextual menu or the Layer ► 
Save As… menu are not exactly the same.

The former has a little fewer options that could be specified than the 
latter.

Anyway, the most important difference is that the former dialog window 
saves the memory layer to disk and then it substitutes the memory layer 
in the project with the layer saved to disk, while the latter saves the 
memory layer to disk without substituting it with the layer saved to 
disk which is however subsequently added by default to the project or 
optionally not added to the project.

Best regards.

Andrea Giudiceandrea


[1] 
https://docs.qgis.org/3.28/en/docs/user_manual/managing_data_source/create_layers.html#creating-a-new-temporary-scratch-layer