[GRASSLIST:10057] v.to.db syntax

GRASS GRASS user
1

Could someone expand on the syntax for the command v.to.db?

I have a vector file that came with bad y coordinate values in the downloaded dbf attribute table. Therefor when I read the shape file into grass with v.in.ogr (I'm connected to postgresql database), the y value in attribute table in pg is also wrong. I want to re-write the y coordinates in the attribute table with the correct geometry from the vector file.

I tried:

  v.to.db NAME_OF_GRASS_VECTOR option=coor col=x,y

The command appeared to run (albit it took a while) but did not re-write the attibute table associated with the vector. Anyone see what I messed up?

Thanks,

Kirk

2

Kirk,

Here's one thought. Are the columns actually named "x" and "y"?
You need to specify real column names.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
Arizona State University
Tempe, AZ 85287-2402

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

From: "Kirk R. Wythers" <kwythers@umn.edu>
Date: Mon, 30 Jan 2006 15:23:21 -0600
To: List Users GRASS <GRASSLIST@baylor.edu>
Cc: Blazek Radim <blazek@itc.it>
Subject: [GRASSLIST:10057] v.to.db syntax

Could someone expand on the syntax for the command v.to.db?

I have a vector file that came with bad y coordinate values in the
downloaded dbf attribute table. Therefor when I read the shape file
into grass with v.in.ogr (I'm connected to postgresql database), the
y value in attribute table in pg is also wrong. I want to re-write
the y coordinates in the attribute table with the correct geometry
from the vector file.

I tried:

  v.to.db NAME_OF_GRASS_VECTOR option=coor col=x,y

The command appeared to run (albit it took a while) but did not re-
write the attibute table associated with the vector. Anyone see what
I messed up?

Thanks,

Kirk

3

Michael,

Thanks for the response. As it turns out the columns were actually named "x" and "y". I re-ran the command v.to.db NAME_OF_GRASS_VECTOR option=coor col=x,y and it worked perfectly (I have no idea what was going on earlier... oh well).

For Markus and Tom, thanks for all your suggestions as well. As it turns out the simple explanation was the x and y attributes in the original .dbf file (that came with the .shp file) were just plain broken. In that their coordinates did not match up the correct geometry in the .shp file.
Again, I have no idea why. However, it does not matter, because of the very cool command v.to.db, which did what it promised and extracted the correct geometry from the vector and wrote it to the x and y attibutes in the associated database table.

This was a case of Murphy's Law where, if you try a new analysis or command, the dataset that you are try it out on will inevitably be faulty in some way. That way, when your analysis does not work, you will be left thinking that you did something wrong, and then spend two days figuring out that it was not you... it was the data. :wink:

Thanks again,

On Jan 31, 2006, at 12:50 AM, Michael Barton wrote:

Kirk,

Here's one thought. Are the columns actually named "x" and "y"?
You need to specify real column names.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
Arizona State University
Tempe, AZ 85287-2402

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

From: "Kirk R. Wythers" <kwythers@umn.edu>
Date: Mon, 30 Jan 2006 15:23:21 -0600
To: List Users GRASS <GRASSLIST@baylor.edu>
Cc: Blazek Radim <blazek@itc.it>
Subject: [GRASSLIST:10057] v.to.db syntax

Could someone expand on the syntax for the command v.to.db?

I have a vector file that came with bad y coordinate values in the
downloaded dbf attribute table. Therefor when I read the shape file
into grass with v.in.ogr (I'm connected to postgresql database), the
y value in attribute table in pg is also wrong. I want to re-write
the y coordinates in the attribute table with the correct geometry
from the vector file.

I tried:

  v.to.db NAME_OF_GRASS_VECTOR option=coor col=x,y

The command appeared to run (albit it took a while) but did not re-
write the attibute table associated with the vector. Anyone see what
I messed up?

Thanks,

Kirk