QGIS » QGIS Application

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.

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.

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

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

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?

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

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.

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.

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?

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.

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

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!