Bug report #6696: Raster calculator - "in memory raster" - QGIS Application - QGIS Issue Tracking

Bug report #6696

Raster calculator - "in memory raster"

Added by Jonathan Moules over 11 years ago. Updated over 5 years ago.

Status:	Closed
Priority:	Normal
Assignee:	-
Category:	Rasters
Affected QGIS version:	2.2.0	Regression?:	No
Operating System:		Easy fix?:	No
Pull Request or Patch supplied:	No	Resolution:	end of life
Crashes QGIS or corrupts data:	No	Copied to github as #:	15861

Description

Using raster calculator, I have a simple calculation - (36SK10se@1 + 36SK10se@1) / 2 - If I use all the defaults, setting the output type to TIF say and setting a directory it works.

If however I set output format to "In Memory Raster" (leaving everything else), then I get this error upon trying to execute it:
"C:/tempdata/asdf.tif is not a valid or recognized raster data source"

C:/tempdata/asdf.tif is what I specified as the "output layer".

There is some combination of the below bugs here, depending on desired behaviour:
a) It's not possible to press "ok" until an output layer has been specified. Even if the format is "in memory raster".
b) The In Memory Raster shouldn't be trying to write anything out so shouldn't care what's in the "output layer" field.
c) The error message implies that it is reading the data (it being a "source"). The error could instead say: "XYZ is not a valid or recognized raster destination"

History

#1 Updated by Jonathan Moules over 11 years ago

Also occurs in master

#2 Updated by Jonathan Moules over 10 years ago

Proposed solution - don't require an "output layer" to be specified when the output format is "In Memory Raster".
Also grey out the "output layer" box when this is selected.

#3 Updated by Martin Dobias over 10 years ago

So there are some GUI issues - for those I would suggest introducing a checkbox "keep in memory only" that would disable the format combo box + output layer. But more importantly the problem is that the output dataset is closed and then reopened - for in memory data it is fatal as all data are lost on close. Output raster layer in QGIS would need to be constructed from an existing GDAL dataset handle - there is currently no way of doing that (layers in QGIS are always constructed from URI string).