[GIS] the temporary output layers from QGIS processing algorithms stored

memory-layerqgisqgis-2.18qgis-processing

Context

I have always worked with memory outputs from several QGIS geoalgorithms within the Processing Toolbox. If it wasn't specified a location when saving the result, the output was stored as a temporary layer in a specified path, which was in general something like:

C:\Users\xxxxx\AppData\Local\Temp\processinge252173536ab4ef987fcb13829939857\c35bd5c897f24c5eb13b9aad985b9652\OUTPUT.shp

If the temporary layer wasn't saved before quitting QGIS, it was automatically deleted from the disk.

Issue

Using QGIS 2.18, I casually noted that I'm no longer able to find the temporary output layers in the Temp folder: this behavior appears to only belong to the QGIS geoalgorithms (instead, the temporary outputs from SAGA or GRASS algorithms are still saved in the Temp folder, as usual).

If I select one output from the QGIS geoalgorithms and go to Properties > General, I see something like this in the Layer source field:

Polygon?uuid=29cdbb21-d299-4b01-b735-0004971e1203&crs=EPSG:32632&field=id:integer&field=value:string&field=area:double&field=perim:double

As you can see, there isn't any reference to a path in my disk, so I can't find the physical position of the output.

In Settings > System, I have this path for the temporary files:

C:\Users\xxxxx\AppData\Local\Temp

In the Processing options, instead, I have:

C:\Users\xxxxx\.qgis2\processing\outputs

There is something that I don't know on how the temporary output layers are managed since the current version of QGIS? I encountered this issue using QGIS 2.18, but I don't exclude that it could be started from previous versions of the software.

Best Answer

As @ndawson correctly commented:

They weren't memory layers, they were just shapefiles stored in a temporary location (and subject to all the limitations present in the shapefile format!)

The final note is that the name "memory layer" was improperly used.

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