[GRASSLIST:5295] GRASSRGB size, datatype and use

GRASS GRASS user
1

Hi,
  Thanks for the information about "d.vect.area" that now is "d.vect -a".
I still have a couple of questions. I would like to know what datatype
should be the GRASSRGB column. I'm used text, but I receive a warning
concerning to the length of the field, should it be varchar(11) ? How
can I specify that using db.execute ? is correct to use:

echo "ALTER TABLE table_t ADD COLUMN grassrgb text(11)" | db.execute

I also, would like to be able to use some command like this:

echo "UPDATE table_t SET grassrgb='v1:v2:v3' WHERE cat=xxx "|db.execute

  Where v1, v2, v3 and xxx are values that I can vary systematically or be
the result of a calculation... for example, set the level of gray of a
category accoding to the number of categories [the number is obtained by
COUNT() and the color could be determined by doing something like CAT *
255 / COUNT() ] Is there any way to write such things in the echo part
of db.execute or the only way id through a script ? Besides there is
another problem, when I use 'v1:v2:v3' the "variables" v1, v2, and v3
are taken as text, whereas if I try v1:v2:v3 there is a SQL problem with
the character : ?
   Someone knows how to do this ?
   Futher more is it possible to use a file to specify the grassrgb values
when I use d.vect -a ???

   THANKS

   D.

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2

On Tue, January 11, 2005 18:38, DrakeGis said:

Hi,
  Thanks for the information about "d.vect.area" that now is "d.vect -a".
I still have a couple of questions. I would like to know what datatype
should be the GRASSRGB column. I'm used text, but I receive a warning
concerning to the length of the field, should it be varchar(11) ? How
can I specify that using db.execute ? is correct to use:

echo "ALTER TABLE table_t ADD COLUMN grassrgb text(11)" | db.execute

I don't know. Have you tried :wink:

Radim ?

Depending on the database format you use (dbf, postgresql, etc) You could try
with a database access program such as openoffice (via data source) or
pgaccess to do the job.

I also, would like to be able to use some command like this:

echo "UPDATE table_t SET grassrgb='v1:v2:v3' WHERE cat=xxx "|db.execute

  Where v1, v2, v3 and xxx are values that I can vary systematically or be
the result of a calculation... for example, set the level of gray of a
category accoding to the number of categories [the number is obtained by
COUNT() and the color could be determined by doing something like CAT *
255 / COUNT() ] Is there any way to write such things in the echo part
of db.execute or the only way id through a script ?

I think you might be better off with a script.

Besides there is
another problem, when I use 'v1:v2:v3' the "variables" v1, v2, and v3
are taken as text, whereas if I try v1:v2:v3 there is a SQL problem with
the character : ?

Are you talking about the actual caracters v1, v2, v3 which _are_ text, or are
you speaking of them as numbers ? If you have defined vX as being a number
(via export v1=1) then you might have to use $v1 instead of v1.

   Futher more is it possible to use a file to specify the grassrgb values
when I use d.vect -a ???

I don't think so. But again, by using openoffice or something similar, it
would not be that different from writing into a file...

Moritz

3

On Wed, Jan 12, 2005 at 03:10:08PM +0100, Moritz Lennert wrote:

On Tue, January 11, 2005 18:38, DrakeGis said:
> Hi,
> Thanks for the information about "d.vect.area" that now is "d.vect -a".
> I still have a couple of questions. I would like to know what datatype
> should be the GRASSRGB column. I'm used text, but I receive a warning
> concerning to the length of the field, should it be varchar(11) ? How
> can I specify that using db.execute ? is correct to use:
>
> echo "ALTER TABLE table_t ADD COLUMN grassrgb text(11)" | db.execute

I don't know. Have you tried :wink:

Try this:

echo "ALTER TABLE table_t ADD COLUMN grassrgb varchar(11)" | db.execute
                                               ^^^^^^^^

Markus