[GRASS-dev] [GRASS GIS] #2814: digitizer crashes, leaves vector broken

#2814: digitizer crashes, leaves vector broken
-------------------------------+-------------------------
Reporter: harrikoo | Owner: grass-dev@…
     Type: defect | Status: new
Priority: normal | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Keywords: digitizer, vector | CPU: Unspecified
Platform: Unspecified |
-------------------------------+-------------------------
I have yet to build a case where this manifests consistently, but it has
appeared several times. I describe some features of the defect:

1. Usually happens when crossing lines and boundaries: moving vertices
around so that existing lines cross, thus creating new lines/areas. But
not always; I haven't found a regular pattern yet.

2. digitizer crashes immeadiately, as does wxgui

3. topology is not built. After v.build, the coordinate file is larger
than it should be, and v.build reports that the vector contains lots of
incorrect boundaries. v.build is unable to fix these, and using v.clean
does not seem to help either.

4. the vector cannot be opened in the digitizer, as the digitizer crashes
immediately upon opening the corrupted vector.

5. the data in the vector can be salvaged with a judicious used of 'v.edit
tool=delete' or by using 'v.extract' with right criteria to move the
correct features to a new vector.

I can send a coor file of a vector demonstrating the results of this bug
to someone interested in seeing it.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------
Changes (by mlennert):

* priority: normal => blocker

Comment:

This seems to be a rebirth of #2439 and #2476.

I've just tested on trunk and on 7.0.3RC1 and I can confirm the following
behaviours of g.gui.vdigit:

1.

* Digitize one straight line.
* Digitize a second straight line that crosses the first
* Hit undo

=> Segmentation fault

2.

* Digitize an area with the last line crossing the first
* Undo

=> Segmentation fault

3.

* Digitize one straight line
* Undo
* Redo

=> Segmentation fault

I also again can see the same issue discussed in #2439 concerning the
dotted guiding line for digitization disappearing.

I don't know when this all reappeared, but at the time I'd done some
extensive testing and MarkusM's fixes worked for me. No idea why the issue
is back.

Declaring this as a blocker for 7.0.3 as this should just work, but could
others test and confirm ?

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:1&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by annakrat):

Replying to [comment:1 mlennert]:
> This seems to be a rebirth of #2439 and #2476.
>
> I've just tested on trunk and on 7.0.3RC1 and I can confirm the
following behaviours of g.gui.vdigit:
>
I can confirm it.

There were no related changes in wxpython/vdigit since the fixes, it could
be caused by changes in the library too, but I can't assess that. You
could try to isolate the issue by updating svn tree to some previous
versions. However, segmentation faults don't have to occur every time
which makes it difficult to find.
>

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:2&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by mlennert):

Replying to [comment:2 annakrat]:
> You could try to isolate the issue by updating svn tree to some previous
versions. However, segmentation faults don't have to occur every time
which makes it difficult to find.

In my case the segfaults are systematic, so it's not that difficult.

I've been able to narrow down the range to somewhere between r64187 and
r64221, but have to stop now. MarkusM has done quite some work on the
vector libs during the time. Probably something in that is the culprit.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:3&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by mlennert):

Replying to [comment:3 mlennert]:
> Replying to [comment:2 annakrat]:
> > You could try to isolate the issue by updating svn tree to some
previous versions. However, segmentation faults don't have to occur every
time which makes it difficult to find.
>
> In my case the segfaults are systematic, so it's not that difficult.
>
> I've been able to narrow down the range to somewhere between r64187 and
r64221, but have to stop now. MarkusM has done quite some work on the
vector libs during the time. Probably something in that is the culprit.
>

Found the change at fault: r64214. Now we need to identify what in that
change causes the segfault.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:4&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by neteler):

Replying to [comment:4 mlennert]:
> Found the change at fault: r64214. Now we need to identify what in that
change causes the segfault.

Cannot you run it all through "gdb" for a backtrace?

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:5&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by martinl):

Replying to [comment:5 neteler]:
> Replying to [comment:4 mlennert]:
> > Found the change at fault: r64214. Now we need to identify what in
that change causes the segfault.
>
> Cannot you run it all through "gdb" for a backtrace?

r64214 broke restore_line logic, I am working on this issue (unfortunately
too much busy today). Hopefully tomorrow I will be able to provide a
tested patch.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:6&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by martinl):

Replying to [comment:1 mlennert]:
> 1.
>
> * Digitize one straight line.
> * Digitize a second straight line that crosses the first
> * Hit undo
>
> => Segmentation fault
>
> 2.
>
> * Digitize an area with the last line crossing the first
> * Undo
>
> => Segmentation fault
>
>
> 3.
>
> * Digitize one straight line
> * Undo
> * Redo
>
> => Segmentation fault

1. and 3. should be fixed in r67508. I don't understand 2. (what does mean
"an area with the last line crossing the first"?)

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:7&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by mlennert):

Replying to [comment:7 martinl]:
> Replying to [comment:1 mlennert]:
> > 1.
> >
> > * Digitize one straight line.
> > * Digitize a second straight line that crosses the first
> > * Hit undo
> >
> > => Segmentation fault
> >
> > 2.
> >
> > * Digitize an area with the last line crossing the first
> > * Undo
> >
> > => Segmentation fault
> >
> >
> > 3.
> >
> > * Digitize one straight line
> > * Undo
> > * Redo
> >
> > => Segmentation fault
>
> 1. and 3. should be fixed in r67508. I don't understand 2. (what does
mean "an area with the last line crossing the first"?)

2. means: digitize an area, but instead of closing the area correctly, you
draw the last (closing) line in a way that it intersects the first (or
actually any of the other lines making up your area) and then you undo.
It's just another case of intersecting lines causing problems with undo...

Everything works great now. Thanks a lot for this fix !

Could others help testing if they can find any bad side effects of this
change ?

If not, and unless someone (MarkusM ?) has any special reason to delay
this, I would suggest to backport this to release70

Moritz

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:8&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by mlennert):

Replying to [comment:5 neteler]:
> Replying to [comment:4 mlennert]:
> > Found the change at fault: r64214. Now we need to identify what in
that change causes the segfault.
>
> Cannot you run it all through "gdb" for a backtrace?

Well, I've never managed to debug GUI issues via gdb, notably since
g.gui.vdigit is a Python script, not a C-module. Do you have tips on how
to debug such issues with gdb ?

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:9&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by annakrat):

Replying to [comment:9 mlennert]:
> Replying to [comment:5 neteler]:
> > Replying to [comment:4 mlennert]:
> > > Found the change at fault: r64214. Now we need to identify what in
that change causes the segfault.
> >
> > Cannot you run it all through "gdb" for a backtrace?
>
> Well, I've never managed to debug GUI issues via gdb, notably since
g.gui.vdigit is a Python script, not a C-module. Do you have tips on how
to debug such issues with gdb ?

For this case I use gdb trough QtCreator, you can attach external process
- the gui and if gui crashes, it will show where in the c code it
happened. This is quite easy, there is a wiki on using QtCreator with
GRASS[https://grasswiki.osgeo.org/wiki/Using_QtCreator_for_GRASS_C_development
here]

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:10&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by annakrat):

Replying to [comment:8 mlennert]:
> Could others help testing if they can find any bad side effects of this
change ?
>
The test cases work now for me as well.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:11&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by mlennert):

Replying to [comment:11 annakrat]:
> Replying to [comment:8 mlennert]:
> > Could others help testing if they can find any bad side effects of
this change ?
> >
> The test cases work now for me as well.

Thanks for testing (and thanks for the tips on QtCreator).

AFAICS, the functions that were changed are only used in the wx digitizer,
so I don't have the feeling that there is much to be expected in terms of
unwanted side effects. I, therefore, think that we can backport.

Martin, will you do that, or should I (I don't know how much the code of
the digitizer has changed between trunk and release70) ?

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:12&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by martinl):

Replying to [comment:12 mlennert]:
> Martin, will you do that, or should I (I don't know how much the code of
the digitizer has changed between trunk and release70) ?

done in r67517

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:13&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by martinl):

Replying to [ticket:2814 harrikoo]:
> I have yet to build a case where this manifests consistently, but it has
appeared several times. I describe some features of the defect:
>
> 1. Usually happens when crossing lines and boundaries: moving vertices
around so that existing lines cross, thus creating new lines/areas. But
not always; I haven't found a regular pattern yet.
>
> 2. digitizer crashes immeadiately, as does wxgui

I am not sure of originally reported issue is fixed (there is no undo
mentioned)

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:14&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by mlennert):

Replying to [comment:14 martinl]:
> Replying to [ticket:2814 harrikoo]:
> > I have yet to build a case where this manifests consistently, but it
has appeared several times. I describe some features of the defect:
> >
> > 1. Usually happens when crossing lines and boundaries: moving vertices
around so that existing lines cross, thus creating new lines/areas. But
not always; I haven't found a regular pattern yet.
> >
> > 2. digitizer crashes immeadiately, as does wxgui
>
> I am not sure of originally reported issue is fixed (there is no undo
mentioned)

I've tried to reproduce, but can't. We would need a reproducible
example...

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:15&gt;
GRASS GIS <https://grass.osgeo.org>

From: "GRASS GIS" <trac@osgeo.org>
Subject: Re: [GRASS GIS] #2814: digitizer crashes, leaves vector broken
Date: Fri, 08 Jan 2016 09:56:04 -0000

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by mlennert):

Replying to [comment:14 martinl]:
> Replying to [ticket:2814 harrikoo]:
> > I have yet to build a case where this manifests consistently, but it
has appeared several times. I describe some features of the defect:
> >
> > 1. Usually happens when crossing lines and boundaries: moving vertices
around so that existing lines cross, thus creating new lines/areas. But
not always; I haven't found a regular pattern yet.
> >
> > 2. digitizer crashes immeadiately, as does wxgui
>
> I am not sure of originally reported issue is fixed (there is no undo
mentioned)

I've tried to reproduce, but can't. We would need a reproducible
example...

I've been trying to comment on this one, but the Trac login does not
work, so I can't get into the system.

I've been following the discussion with interest. I could reproduce
the bugs discovered by 'mlennert', but the results were not the same:
the coor file did have extra data, but could be opened with
g.gui.vdigit, after which the file was quite ok.

Good to have these bugs fixed, too; but in the original cases, the
resulting vector was in such a state, that g.gui.vdigit was not able
to open it any more.

But as I wrote, I have not been able to create a reproducible example;
but the exactly same phenomenon has happened a few times during the
last two months I've been using the g.gui.vdigit extensively. Now that
I know what to wait for, I'll try to figure out what exactly I did
before the crash next time. (g.gui.vdigit does crash quite a lot, but
usually the results are harmless.)

Best,

Harri K.

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------

Comment (by harrikoo):

Replying to [comment:15 mlennert]:
> Replying to [comment:14 martinl]:
> > I am not sure of originally reported issue is fixed (there is no undo
mentioned)
>
> I've tried to reproduce, but can't. We would need a reproducible
example...

I have followed this discussion with interest. I could reproduce the bugs
discovered by [comment:1 mlennert], but the results were actually not the
same. In my original case, the resulting vector was so corrupted, that it
could not be fixed, nor opened again with g.gui.vdigit; in mlennert's bugs
the vectors could be opened with g.gui.vdigit after rebuilding the
topology. And it is true, that in my case, ''undo'' never played any part.

So my statement would be, that the bug in my original report is ''not''
fixed; but since I cannot figure out how to reproduce it, I would also
say, that the ''blocker'' status might be a bit too strong for this one.

But it was good to have other bugs fixed. (I did have the feeling that the
undo/redo-buttons should not be touched.) I'll try to figure out if there
is a consistent way to reproduce my bug.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:16&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: critical | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------
Changes (by martinl):

* priority: blocker => critical

Comment:

Replying to [comment:16 harrikoo]:

> But it was good to have other bugs fixed. (I did have the feeling that
the undo/redo-buttons should not be touched.) I'll try to figure out if
there is a consistent way to reproduce my bug.

OK, I took liberty to downgrade the priority.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:17&gt;
GRASS GIS <https://grass.osgeo.org>

#2814: digitizer crashes, leaves vector broken
--------------------------+-------------------------------
  Reporter: harrikoo | Owner: grass-dev@…
      Type: defect | Status: new
  Priority: blocker | Milestone: 7.0.3
Component: wxGUI | Version: 7.0.2
Resolution: | Keywords: digitizer, vector
       CPU: Unspecified | Platform: Unspecified
--------------------------+-------------------------------
Changes (by harrikoo):

* priority: critical => blocker

Comment:

Now it just happened again! I was drawing a test vector and crossing lines
and boundaries, breaking them and merging them, and then in the end,
deleting extra lines; immediately after the deletion of one line (select
with left, confirm with right) the digitizer crashed. This was not the
first line I deleted, perhaps the 20th, so it was something particular
about that line.

V.build reports errors in the file:

{{{
GRASS 7.0.2RC2 (Nemi):~/grass/Nemi/terracewall > v.build test
WARNING: Coor file of vector map <test@terracewall> is larger than it
          should be (5326 bytes excess)
Building topology for vector map <test@terracewall>...
Registering primitives...
35 primitives registered
80 vertices registered
Building areas...
  100%
4 areas built
2 isles built
Attaching islands...
  100%
Attaching centroids...
  100%
Number of nodes: 25
Number of primitives: 35
Number of points: 0
Number of lines: 8
Number of boundaries: 20
Number of centroids: 7
Number of areas: 4
Number of isles: 2
WARNING: Number of centroids exceeds number of areas: 7 > 4
WARNING: Number of incorrect boundaries: 14
WARNING: Number of centroids outside area: 3
WARNING: Number of duplicate centroids: 1
}}}

Especially the number of incorrect boundaries is way too high. Otherwise
the figures seem ok.

The line I was deleting was at one end sharing a vertex with an area.

And then, `g.gui.vdigit` crashes with this message:

{{{
Coor file of vector map <test@terracewall> is larger than it should be
(5326 bytes excess)
Current region rows: 300, cols: 450
G_malloc: unable to allocate 18446744073709551608 bytes of memory at
lib/vector/vedit/render.c:312
}}}

Looking at the file with `v.info` shows wrong extents:

{{{
WARNING: Coor file of vector map <test@terracewall> is larger than it
          should be (5326 bytes excess)
+----------------------------------------------------------------------------+
  | Name: test
|
  | Mapset: terracewall
|
  | Location: Nemi
|
  | Database: /home/harri/grass
|
  | Title:
|
  | Map scale: 1:1
|
  | Name of creator: harri
|
  | Organization:
|
  | Source date: Thu Jan 7 20:58:54 2016
|
  | Timestamp (first layer): none
|
|----------------------------------------------------------------------------|
  | Map format: native
|
|----------------------------------------------------------------------------|
  | Type of map: vector (level: 1)
|
  |
|
  | Number of points: 0 Number of centroids: 7
|
  | Number of lines: 8 Number of boundaries: 20
|
  | Number of areas: 0 Number of islands: 0
|
  |
|
  | Map is 3D: No
|
  | Number of dblinks: 0
|
  |
|
  | Projection: Oblique Mercator
|
  |
|
  | N: 5075.53088803 S: 0
|
  | E: 5174.83237245 W: 0
|
  |
|
  | Digitization threshold: 0
|
  | Comment:
|
  |
|
+----------------------------------------------------------------------------+
}}}
I have not drawn anything near (0,0), all the coordinates should be well
above (4800,4800).

I can try to run some debugging commands, if someone just lets me know a
suitable command line...

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2814#comment:18&gt;
GRASS GIS <https://grass.osgeo.org>