[GRASS-user] bug?: v.to.db wrong area

[Achim Kisseler]

I think "v.dissolve" corrupted it.

I solved it by making a raster map and then a vector map again.

Thanks, Markus and Pablo,

Achim


Achim Kisseler schrieb:
> I made the grid with:
> 
> -%<--
> v.mkgrid --overwrite map=$1_grid_all grid="$north_south,$east_west"
> position=coor coor="$southwest_corner" box="0:30,0:30"
> 
> echo "
> ########################################
> ## shrink grid to land-surface"
> sqlite3 $2 "drop table $1_grid_patched"
> v.overlay --o ainput=$1_grid_all binput=$1_area output=$1_grid_patched
> v.db.addcol map=$1_grid_patched columns="keep INT"
> sqlite3 $2 "UPDATE $1_grid_patched SET keep=1 WHERE (NOT b_cat IS NULL
> OR  ((a_row*1000)+a_col) IN (SELECT (a_row*1000)+a_col FROM
> $1_grid_patched WHERE NOT b_cat IS NULL))"
> v.extract input=$1_grid_patched output=$1_grid_extracted where="keep=1"
> --overwrite
> v.db.addcol map=$1_grid_extracted columns="dissolve INT"
> sqlite3 $2 "UPDATE $1_grid_extracted SET dissolve=((a_row*1000)+a_col)"
> v.dissolve --overwrite input=$1_grid_extracted output=$1_grid
> column=dissolve layer=1
> 
> (...)
> 
> sh renew_cats.sh $1_grid 2 centroid
> db.droptable -f table=$1_grid
> v.db.connect -d map=$1_grid
> v.db.addtable map=$1_grid
> -%<--
> 
> In the picture:
> yellow grids seem ok (301.444-279.003 km²)
> one is 194.532
> the rest is 2.545.231-11.559.210
> 
> Achim
> 
> 
> 
> Pablo Carreira schrieb:
>> Achim, how was the grid generated? Could you put some fo the results here?
>>
>>
>> Pablo.
>>
>>
>>> Date: Mon, 7 Dec 2009 18:32:14 +0100
>>> From: ak7 at jupiter.uni-freiburg.de
>>> To: markus.metz.giswork at googlemail.com
>>> Subject: Re: [GRASS-user] bug?: v.to.db wrong area
>>> CC: grass-user at lists.osgeo.org
>>>
>>> Hi Markus,
>>>
>>> its the same with hectares; kilometers writes out the result in
>>> square-kilometers.
>>>
>>> Achim
>>>
>>> Markus Metz schrieb:
>>>> Achim Kisseler wrote:
>>>>> Hi,
>>>>>
>>>>> I am using
>>>>>
>>>>> v.to.db map=af_grid option=area columns=area type=centroid
>>>>> units=kilometers
>>>>>
>>>> try units=hectares, kilometers are not an areal unit, don't know why
>>>> v.to.db executes at all
>>>>
>>>> you can cross-check the results by querying the map
>>>>
>>>> hope that helps,
>>>>
>>>> Markus M
>>>>
>>>>> (in GRASS65 opensuse 11.1 64)
>>>>>
>>>>> to calculate the area size. Some of the areas are very wrong. Its a
>> grid
>>>>> in lat-lon, where areas should be nearly equal in size.
>>>>>
>>>>> Is this a known bug? I don't guess so.
>>>>> Do I something wrong?
>>>>>
>>>>> Thanks,
>>>>> Achim
>>>>>
>>>>> PS:
>>>>> already did v.clean, r.mask -r (<- should not be have an effect)
>>>>> _______________________________________________
>>>>> grass-user mailing list
>>>>> grass-user at lists.osgeo.org
>>>>> http://lists.osgeo.org/mailman/listinfo/grass-user
>>>>>
>>>>>
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>> ------------------------------------------------------------------------
>> Agora a pressa é amiga da perfeição. Chegou Windows 7. Conheça.
>> <http://www.microsoft.com/brasil/windows7/default.html?WT.mc_id=1539>
>>
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>>
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