Bug report #19276

GRASS 7 digitising bug 'Could not Commit changes'

Added by Chris Kahler about 2 years ago. Updated over 1 year ago.

Status:Open
Priority:Normal
Assignee:-
Category:GRASS
Affected QGIS version:3.5(master) Regression?:No
Operating System:Mac OS 10.13.1 (High Sierra), Windows Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:27104

Description

Hi, I'm not able to consistently edit either new GRASS polygon layers or existing ones in QGIS 3.2. This problem has persisted for a few versions of QGIS going back into the later version 2 releases. The error message always includes the text "Geometry type is not compatible with the current layer". It seems as though QGIS is not able to distinguish between boundary and line layers in GRASS. Note that even standalone versions of GRASS 7 (last release tested was 7.4.1) are not stable when digitising and GRASS usually crashes when entering digitising mode.
Digitising and editing vectors topologically has always been an attribute of GRASS that I've valued - this function has been broken or buggy for more than a year now in both GRASS releases and QGIS releases.
Able to provide link to screen capture while experiencing this error
Regards, CK

History

#1 Updated by Chris Kahler about 2 years ago

  • Assignee deleted (Chris Kahler)

#2 Updated by Giovanni Manghi about 2 years ago

  • Status changed from Open to Feedback

What is the last version where you were able to edit/digitize GRASS vectors?

Have you tested if this problem is platform specific?

#3 Updated by Jürgen Fischer about 2 years ago

  • Subject changed from QGIS 3.2 GRASS 7 digitising bug 'Could not Commit changes' to GRASS 7 digitising bug 'Could not Commit changes'

#4 Updated by Chris Kahler about 2 years ago

Hi Giovanni,
1) hard to be sure when GRASS digitising last worked well, however, I can say I used '2.8.2-Wien' in December 2015 to create a vector map from scratch with no real problems. From memory, this version used a GRASS digitising tool set borrowed directly from GRASS (that is, before GRASS was integrated with QGIS native vector edit tools). The GRASS toolset wasn't as capable as the modern QGIS editing toolset is, however, it worked as expected on GRASS vectors. From memory this was with GRASS 6 versions.
Problems started when GRASS digitising tools were done away with and GRASS began to be integrated with QGIS edit tools. This is one of a number of issues I've had attempting to edit vectors in GRASS using the native QGIS tools. Others, which may be related include i) not being able to delete centroids in edit mode and ii) inconsistent behaviour of node edit tool (QGIS 3.2).

2) I can't test on other platforms unfortunately. I have seen Underdark's (Anita Graser) video editing using GRASS vector layers in QGIS 3.1 and it seemed to work for her. Not sure what system she uses.

#5 Updated by Giovanni Manghi about 2 years ago

Chris Kahler wrote:

Hi Giovanni,
1) hard to be sure when GRASS digitising last worked well, however, I can say I used '2.8.2-Wien' in December 2015 to create a vector map from scratch with no real problems. From memory, this version used a GRASS digitising tool set borrowed directly from GRASS (that is, before GRASS was integrated with QGIS native vector edit tools). The GRASS toolset wasn't as capable as the modern QGIS editing toolset is, however, it worked as expected on GRASS vectors. From memory this was with GRASS 6 versions.
Problems started when GRASS digitising tools were done away with and GRASS began to be integrated with QGIS edit tools. This is one of a number of issues I've had attempting to edit vectors in GRASS using the native QGIS tools. Others, which may be related include i) not being able to delete centroids in edit mode and ii) inconsistent behaviour of node edit tool (QGIS 3.2).

2) I can't test on other platforms unfortunately. I have seen Underdark's (Anita Graser) video editing using GRASS vector layers in QGIS 3.1 and it seemed to work for her. Not sure what system she uses.

I'm almost sure Anita uses Windows. Can you point me to such video? thanks.

#6 Updated by Chris Kahler about 2 years ago

My mistake, not Underdark. URL here: https://youtu.be/AubBmm3kL2E
"QGIS GRASS Plugin - editing of multiple layers" by Radim Blazek.

#7 Updated by Chris Kahler about 2 years ago

A video of the issue while editing GRASS layer on my system: https://www.youtube.com/watch?v=elnprq7_bqk

#8 Updated by Giovanni Manghi about 2 years ago

Chris Kahler wrote:

A video of the issue while editing GRASS layer on my system: https://www.youtube.com/watch?v=elnprq7_bqk

does it work as expected on 2.18?

#9 Updated by Chris Kahler almost 2 years ago

Hi Giovanni, apologies for absence, I've been on leave: no, it didn't work reliably on version 2.18 either.

#10 Updated by Chris Kahler almost 2 years ago

Example video of GRASS bug in QGIS2.18 here (https://youtu.be/jFOLtx5qsog). Results in the error 'Geometry type Linestring not compatible with provider type Polygon' when attempting to digitise in GRASS.

#11 Updated by Chris Kahler almost 2 years ago

I recently tested QGIS 2.8.9 with GRASS 6.4 on a Windows XP virtual machine on mac. All edit tools worked without the problems given above (although it would crash on exiting edit mode). I installed QGI 2.8.1 on my mac (the only 2.8 version I could find for mac)and had some luck although GRASS couldn't find it's modules (eg. v.build). Existing GRASS vectors could be edited to a point although cleaning and other functions weren't available due to the module problem. With the ongoing integration of GRASS into QGIS and the development of GRASS from version 6 to 7 I suppose the cause of these problems will be hard to track down.

Editing vectors with the digitiser is such an elementary function it's surprising it no longer works.

#12 Updated by Giovanni Manghi almost 2 years ago

  • Status changed from Feedback to Open

Editing vectors with the digitiser is such an elementary function it's surprising it no longer works.

editing GRASS vectors is all but an obvious task, both for users as also for developers (because of the GRASS vector data model). The work on 2.* was done basically by 1 developer (a GRASS/QGIS developer), but I haven't seen him very active on the QGIS 3 development front. If this is a functionality (editing/digitizing GRASS vectors in QGIS 3) you need evaluate the possibility to support the fix for this specific data source.

#13 Updated by Chris Kahler almost 2 years ago

Thanks Giovanni, good suggestion. I've just checked the QGIS3 webpage to see if I can support a fix - no luck. Do I need to contact developers directly? If not how can I support a fix for this issue?

#14 Updated by Chris Kahler almost 2 years ago

A solution of sorts: after trial and error checking with previous versions of GQIS, I found 2.14.8-1 to work consistently when digitising in GRASS. All GRASS (apparently version 6) modules appear to be available.

#15 Updated by Giovanni Manghi almost 2 years ago

Chris Kahler wrote:

A solution of sorts: after trial and error checking with previous versions of GQIS, I found 2.14.8-1 to work consistently when digitising in GRASS. All GRASS (apparently version 6) modules appear to be available.

this is expected: the major overhaul of GRASS digitizing tools was done for QGIS 2.14 LTR

#16 Updated by Giovanni Manghi almost 2 years ago

Chris Kahler wrote:

Thanks Giovanni, good suggestion. I've just checked the QGIS3 webpage to see if I can support a fix - no luck. Do I need to contact developers directly? If not how can I support a fix for this issue?

raise your question in the developers mailing list, thanks!

#17 Updated by Loïc BARTOLETTI over 1 year ago

  • Operating System changed from Mac OS 10.13.1 (High Sierra) to Mac OS 10.13.1 (High Sierra), Windows

Tested and confirmed on Windows and FreeBSD on master, 3.4 with Grass 7.4 and 7.6

#18 Updated by Giovanni Manghi over 1 year ago

  • Affected QGIS version changed from 3.2 to 3.5(master)

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