[GRASSLIST:3624] Re: v.surf.idw

[Radim Blazek]

How did you make your vector temp20000130180000?
I guess that you have run something like 
cat temp20000130180000 | v.in.ascii catcol=4
In that case a category assigned to ALL points is '4'
and all points are linked to 4. row (data = -2).
Try to query the vector by d.what.vect.

Radim


On Monday 07 June 2004 14:12, Sabine Grabner wrote:
> hello,
>
> i try to interpolate my meteorological data with the following vector data:
>
>
> rsdb=> select * from temp20000130180000;
>     x    |    y    |  z   | parameter | data | refper |        name
> ---------+---------+------+-----------+------+--------+--------------------
>- 10.7814 | 46.7581 | 2070 |         4 |   -7 |      0 | Kurzras
>  11.1667 | 46.6734 |  392 |         4 |   34 |      0 | Meran
>     10.5 |    46.9 | 1360 |         4 |   25 |      0 | Nauders
>   11.023 | 46.8672 | 1938 |         4 |   -2 |      0 | Obergurgl
>   10.875 | 46.9242 | 2850 |         4 |  -44 |      0 | Pitztaler Gletscher
>  10.8794 | 46.9269 | 2850 |         4 |  -46 |      0 | Pitztaler Gletscher
>   10.913 | 46.8594 | 1906 |         4 |   -1 |      0 | Vent
> (7 rows)
>
> rsdb=> \d temp20000130180000
>        Table "public.temp20000130180000"
>   Column   |         Type          | Modifiers
> -----------+-----------------------+-----------
>  x         | double precision      |
>  y         | double precision      |
>  z         | integer               |
>  parameter | integer               |
>  data      | double precision      |
>  refper    | integer               |
>  name      | character varying(20) |
>
> rsdb=>
>
> first question:
> ===============
>
> can anyone tell me how to set a mask as mentioned in the v.surf.idw as the
> command r.mask is neither documented nor does it work on my grass57
>
> second question:
> ================
>
> interpolationg with r.surf.idw all cells does have the same value !?
> i played around with the attribute field, to catch the required collumn
> 'data'. it seems that i got it as every cell has '-2' which matches only to
> this collumn.
> by the way, i casted my int data to float as v.surf.idw matches
> field='which decimal attribute'. is this redundant?
>
> GRASS 5.7.-cvs:~/diss/grassdata > v.surf.idw in=temp20000130180000
> out=temp20000130180000 field=4
> v.surf.idw:
> WARNING: Vector used instead of sites.
> Reading sites map (temp20000130180000) ...         6 sites loaded
> Interpolating raster map <temp20000130180000> ... 2800 rows ... done
> GRASS 5.7.-cvs:~/diss/grassdata > d.rast temp20000130180000
>  100%
> GRASS 5.7.-cvs:~/diss/grassdata > d.what.rast
>
> Buttons
>  Left:  what's here
>  Right: quit
>
> 196272.91666667(E) 5215609.58333333(N)
> temp20000130180000 in sabine57, quant   (-2)
> temp20000130180000 in sabine57, actual  (-2.000000)
>
> 169731.25(E) 5184692.91666667(N)
> temp20000130180000 in sabine57, quant   (-2)
> temp20000130180000 in sabine57, actual  (-2.000000)
> GRASS 5.7.-cvs:~/diss/grassdata >
>
>
> any advice welcome! thanks a lot.
>
> yours, sabine