[GRASS-dev] [GRASS GIS] #1300: WxGUI measure tool gives wrong results

GDAL · March 5, 2011, 1:04pm

#1300: WxGUI measure tool gives wrong results
-------------------------+--------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
     Type: defect | Status: new
Priority: major | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: | Platform: MSWindows Vista
      Cpu: Unspecified |
-------------------------+--------------------------------------------------
Steps to reproduce:
  * Add North arrow and Scale bar to map display
  * Measure scale bar length

gis.m gives correct result (4.9), wxgui allways gives too short result.
4.2Km instead of 5km is a bit too short for simple "shaking hand" error.
Individual bars are given not as 1km, but only 800m.

WinGRASS-6.4.SVN-r45559-1

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Ticket URL: <http://trac.osgeo.org/grass/ticket/1300>
GRASS GIS <http://grass.osgeo.org>

GDAL · March 6, 2011, 12:53am

#1300: WxGUI measure tool gives wrong results
-------------------------+--------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
Type: defect | Status: new
Priority: major | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: | Platform: MSWindows Vista
Cpu: Unspecified |
-------------------------+--------------------------------------------------

Comment(by hamish):

strange, works for me in spearfish.
can you try putting up a 5 km grid as well? (layer manager button to the
left of remove)
also drag the barscale over the grid to make sure those are the same.

I notice it is a bit odd if you add the barscale when the measure tool is
on, after that the measure tool is randomly starting on the page (ref'd to
the barscale overlay canvas instead of the background canvas?) until you
reselect the measure/barscale tools, then it seems to correct itself.
??

Hamish

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Ticket URL: <https://trac.osgeo.org/grass/ticket/1300#comment:1>
GRASS GIS <http://grass.osgeo.org>

GDAL · March 6, 2011, 12:58am

#1300: WxGUI measure tool gives wrong results
-------------------------+--------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
Type: defect | Status: new
Priority: major | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: | Platform: MSWindows Vista
Cpu: Unspecified |
-------------------------+--------------------------------------------------

Comment(by hamish):

also, right-click(?) to restart measure tool ("Do another ...") would be a
nice addition. instead of double left-click to quit tool and then to the
menus to start the tool again.

double left-click seems more natural to me actually, more like a
stopwatch's lap-time vs reset.

Hamish

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Ticket URL: <http://trac.osgeo.org/grass/ticket/1300#comment:2>
GRASS GIS <http://grass.osgeo.org>

GDAL · March 6, 2011, 8:52am

#1300: WxGUI measure tool gives wrong results
-------------------------+--------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
Type: defect | Status: new
Priority: major | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: | Platform: MSWindows Vista
Cpu: Unspecified |
-------------------------+--------------------------------------------------

Comment(by marisn):

Agh! Note to myself: "Never use g.version -r". Failing example on Linux
was more like r45560.

--
Ticket URL: <http://trac.osgeo.org/grass/ticket/1300#comment:3>
GRASS GIS <http://grass.osgeo.org>

GDAL · March 8, 2011, 11:18am

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
Type: defect | Status: new
Priority: major | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------
Changes (by hamish):

* keywords: => measure tool

Comment:

Ok, I can reproduce this on Linux using the latest 6.4.1svn, 6.5svn &
spearfish.

notice that it works in the y-direction but not the x-direction.

well, as long as the white bands are on the left-right, not top-bottom. if
you resize the map window so that the white out-of-region bands are on the
left,right sides, then the measure tool works along the x-asix but not the
y-axis.

so it seems to be using window size not region size, and the bigger the
out-of-region bands, the bigger the d.measure error.

go into preferences and tick the 'constrain' box and it starts to work
better.

also in 6.5svn I notice if I mouse wheel zoom out, the 10km barscale no
longer exactly matches the d.grid lines. (some mm out on the screen) maybe
a d.barscale bug, but I've only known that to be 1px out on the right end.
?

> (Did I sed that current measure tool mouse bindings suck?)

please suggest what would be better. (thoughts on comment:2 ?)

... also, I notice in 6.5svn all maps are missing from d.rast map name
GUI:
{{{
GSelect: invalid item: descriptor 'lower' requires a
'unicode' object but received a 'str'
}}}

Hamish

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/1300#comment:4>
GRASS GIS <http://grass.osgeo.org>

GDAL · March 10, 2011, 11:09pm

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
Type: defect | Status: new
Priority: critical | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------
Changes (by hamish):

* priority: major => critical

Comment:

measure tool bad results also present in 6.4.0+42329 (rc6++), so not a
reversion.
I'm surprised we haven't noticed this earlier. Bumping bug priority as we
shouldn't knowingly report bad data, someone might try and use the results
for something important.

alterbug- I do not get the following with a reasonably recent 6.5.svn45558
when trying to add new maps, will need to check back on my other machine.

{{{
GSelect: invalid item: descriptor 'lower' requires a
'unicode' object but received a 'str'
}}}

Hamish

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/1300#comment:5>
GRASS GIS <http://grass.osgeo.org>

GDAL · March 11, 2011, 2:18am

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
Type: defect | Status: new
Priority: critical | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------

Comment(by hamish):

unicode error filed as #1304.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/1300#comment:6>
GRASS GIS <http://grass.osgeo.org>

GDAL · April 9, 2011, 4:02am

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: grass-dev@…
Type: defect | Status: new
Priority: blocker | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------
Changes (by hamish):

* priority: critical => blocker

Comment:

We are reporting incorrect results, aka data corruption. Bumping this to
blocker.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/1300#comment:7>
GRASS GIS <http://grass.osgeo.org>

GDAL · April 9, 2011, 7:25pm

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: martinl
Type: defect | Status: assigned
Priority: blocker | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------
Changes (by martinl):

* cc: grass-dev@… (added)
* owner: grass-dev@… => martinl
* status: new => assigned

Comment:

Replying to [comment:7 hamish]:
> We are reporting incorrect results, aka data corruption. Bumping this to
blocker.

hopefully fixed in r45883 (and backported to devbr6).

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/1300#comment:8>
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GDAL · April 10, 2011, 3:17am

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: martinl
Type: defect | Status: assigned
Priority: blocker | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------

Comment(by hamish):

Replying to [comment:8 martinl]:
> hopefully fixed in r45883 (and backported to devbr6).

thanks, that passes the 'd.grid 5000' test in spearfish,simple_xy loc'ns +
latest 6.5svn. no difference with using the 'constrain' tick box in prefs
AFAICT.

lat/lon is still reporting meaningless results, in grass7 it should use
m.measure to do the calc so geodesic distance is automatically used if
needed.
(which is basically what I wrote the earlier m.distance.py SWIG version
for*; see also discussion with Radim in the last week about adding a small
sleep to QGIS's r.what mouse-over queries so process doesn't get launched
1000 times per mouse movement)
[*] source:grass/trunk/swig/python/examples/m.distance.py@43200

cheers,
Hamish

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/1300#comment:9>
GRASS GIS <http://grass.osgeo.org>

GDAL · April 10, 2011, 6:50pm

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: martinl
Type: defect | Status: assigned
Priority: blocker | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------

Comment(by martinl):

Replying to [comment:9 hamish]:

> thanks, that passes the 'd.grid 5000' test in spearfish,simple_xy loc'ns
+ latest 6.5svn. no difference with using the 'constrain' tick box in
prefs AFAICT.

backported in r45891

> lat/lon is still reporting meaningless results, in grass7 it should use
m.measure to do the calc so geodesic distance is automatically used if
needed.

probably we should warn user about that. Would be

{{{
Warning: Measuring reports meaningless results for LL projection (geodetic
distance ignored). Check future versions.
}}}

be OK?

--
Ticket URL: <http://trac.osgeo.org/grass/ticket/1300#comment:10>
GRASS GIS <http://grass.osgeo.org>

GDAL · April 10, 2011, 7:52pm

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: martinl
Type: defect | Status: assigned
Priority: blocker | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------

Comment(by hamish):

Replying to [comment:10 martinl]:
> backported in r45891

cheers

> > lat/lon is still reporting meaningless results, in grass7 it should
use
> > m.measure to do the calc so geodesic distance is automatically used if
needed.
>
> probably we should warn user about that. Would be
>
{{{
> Warning: Measuring reports meaningless results for LL projection
(geodetic
> distance ignored). Check future versions.
}}}
>
> be OK?

sounds fine. I'd consider the additional step of disabling the tool after
showing that message. Maybe with "Geodesic distance is not yet supported
by this tool, try d.measure or m.measure.", or something. (apple usability
guide: an error message should say what the trouble was, and give a hint
about where the user should look next/for more info)

veering off-topic a little, but along the same reporting seemingly valid
(but in fact broken) numbers to the user, I've been trying to follow how
the mapscale setting in the drop down menu on the bottom bar of the Map
Display window does its job. Does .ppm[0], .ppm[1] refer to image
width,height? Map scale is fundamentally unknowable if you don't know the
correct pixels-per-mm ratio for the user's particular monitor.
X11,OSX,Window's reports for that have in the past not been very good,
maybe with modern versions it has improved? (being optimistic..)
We get away with it in ps.map because we know the exact size of the paper,
and PostScript exists in that reference frame.
GIMP provides a calibration tool (Prefs->Display->Calibrate) where the
user can press a ruler up to their screen and type in the distance covered
by x,y pixel bars, then hope the user doesn't change screen resolution.

Hamish

ps- At some point I'd like to add the v.in.geodesic addon to trunk, but
I'd like feedback on options & assumptions made before finalizing it and
porting it to python, or turning it into a new C module reusing proj4's
`geod` code if that is preferred.

--
Ticket URL: <http://trac.osgeo.org/grass/ticket/1300#comment:11>
GRASS GIS <http://grass.osgeo.org>

GDAL · April 10, 2011, 10:37pm

#1300: WxGUI measure tool gives wrong results
--------------------------+-------------------------------------------------
Reporter: marisn | Owner: martinl
Type: defect | Status: assigned
Priority: blocker | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Keywords: measure tool | Platform: MSWindows Vista
Cpu: Unspecified |
--------------------------+-------------------------------------------------

Comment(by martinl):

Replying to [comment:11 hamish]:

> sounds fine. I'd consider the additional step of disabling the tool
after showing that message. Maybe with "Geodesic distance is not yet
supported by this tool, try d.measure or m.measure.", or something. (apple
usability guide: an error message should say what the trouble was, and
give a hint about where the user should look next/for more info)

Bearing in mind that we don't expect that wxGUI users know Xmons I
wouldn't note `d.measure` or `m.measure` (no ctypes in relbr64). Would be
r45898 enough for now?

BTW, I have updated `m.distance` in r45895, check also r45897 for wxGUI
measuring tool in LL-locations.

--
Ticket URL: <http://trac.osgeo.org/grass/ticket/1300#comment:12>
GRASS GIS <http://grass.osgeo.org>

GDAL · April 11, 2011, 12:52am

#1300: WxGUI measure tool gives wrong results
------------------------------+---------------------------------------------
  Reporter: marisn | Owner: martinl
      Type: defect | Status: closed
  Priority: blocker | Milestone: 6.4.1
Component: wxGUI | Version: svn-releasebranch64
Resolution: fixed | Keywords: measure tool
  Platform: MSWindows Vista | Cpu: Unspecified
------------------------------+---------------------------------------------
Changes (by hamish):

* status: assigned => closed
* resolution: => fixed

Comment:

Replying to [comment:12 martinl]:
> Bearing in mind that we don't expect that wxGUI users know Xmons
> I wouldn't note `d.measure` or `m.measure`

or necessarily have access to them- point taken, but the user picked up
the tool to get an answer and is now stranded without an answer, and we do
actually have the capability to answer it somehow ...
Mainly I'm trying to think of ways to connect them with the answer they
want. shrug

> Would be r45898 enough for now?

sure, and r45897,9 looks like it will be great.

> BTW, I have updated `m.distance` in r45895,

thanks.

Hamish

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