[GRASS-dev] d.vect -a shows only some elements

Moritz Lennert mlennert at club.worldonline.be
Fri Oct 20 13:23:37 EDT 2006

Moritz Lennert wrote:
> Hamish wrote:
>> Moritz Lennert wrote:
>>> Using d.vect.thematic -u I fill a grassrgb column in the attribute 
>>> table. See http://moritz.homelinux.org/grass/d_vect_a1.png.
>>> But when I try to reuse these colors with d.vect -a, only a few of the
>>> regions get filled (with an additional dissolution of common 
>>> boundaries): http://moritz.homelinux.org/grass/d_vect_a2.png
>>> All of the objects in the map have a color code in the grassrgb
>>> column.
>>> I cannot reproduce this problem in spearfish, so I am a bit lost.
>>> Any ideas ?
>> "with an additional dissolution of common boundaries" is causing the
>> problem.
>> dissolution is based on common cat, but thematic colors are based on
>> "jk" column. areas with a common cat can have different attribute
>> values.
>> e.g. if cat refers to country number, and attr col refers to province
>> area.
> This is not it. The dissolution came from the simple fact, that I used 
> 'd.vect type=area' instead of d.vect type=area,boundary. Sorry, I didn't 
> realize this before.
> So I still have:
> GRASS 6.3.cvs (ESPON):~ > psql -d espon -c "select * from temp where 
> grassrgb is NULL"
>   cat | nuts2 | jk | dkdldm | ab | lmn | grassrgb
> -----+-------+----+--------+----+-----+----------
> (0 lignes)
> and
> GRASS 6.3.cvs (ESPON):~ > psql -d espon -c "select distinct grassrgb 
> from temp"
>   grassrgb
> ----------
>   0:0:255
>   170:0:85
>   255:0:0
>   85:0:170
> So, the grassrgb column is filled as it should. To make sure there is 
> not problem with the colours, I do a seperate d.vect for each range. 
> This works perfectly: http://moritz.homelinux.org/grass/d_vect_a1.png
> But trying to reproduce this with d.vect -a, I get: 
> http://moritz.homelinux.org/grass/d_vect_a2.png.
> As you can see, those regions that are colored, are colored correctly, 
> but not all regions are colored. If I change the color scheme, I get 
> exactly the same results: http://moritz.homelinux.org/grass/d_vect_a3.png
> It is as if d.vect stopped coloring at one point.
> ..
> If I display the map in four d.vect calls with where='grassrgb=255:0:0', 
> etc, it displays fine.
> I also get the same problem if I use d.vect.thematic on the cat column...

I have done some testing, and the problem seems to be in line 224 of 

if (db_CatValArray_get_value (&cvarr_rgb, cat, &cv_rgb) != DB_OK)

db_CatValArray_get_value returns 'not found' for many of the cat values.

I am wondering whether this might be due to the fact that the bsearch in 
db_CatValArray_get_value needs a sorted array, but that the array is not 
sorted as db_select_CatValArray() which creates the array on line 67 of 
the same file only sorts lists of ints or doubles, but not of strings...


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