[GRASS-user] Re: GRASS-user] how to report/measure a vector area?

Use v.report - under the vector/reports menu

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Jan 30, 2012, at 10:00 AM, <grass-user-request@lists.osgeo.org> wrote:

Date: Mon, 30 Jan 2012 17:52:40 +1000
From: Shane Litherland <litherland-farm@bigpond.com>
Subject: [GRASS-user] how to report/measure a vector area?
To: grass-user@lists.osgeo.org
Message-ID: <1327909960.6375.15.camel@Lacebark>
Content-Type: text/plain; charset="UTF-8"

Hi all,

I'm lost. I have looked around in GRASS for how to report the area (e.g.
in hectares) for a vector map that, yes, has area (i.e. centroids and
boundaries).

I cannot find a way to do this. A bit of web searching, even gave some
suggestions this basic facility may not be available in GRASS?? surely
there's something tucked away to do it?

I'm sure I've done something in the past to view vector area data,
though it may have been area data that was already in a table. When I
use the query tool in map display, it tells me 'nothing'. Seems that is
because my vector is not connected to an attribute table. For the
purpose of my exercise I did not need cats for the boundaries/centroids
so I didn't bother with a table connection either. Maybe this is where
I've gone wrong?

I did try vector to raster to try and report on how many raster
cells/area... no luck there either.

I also tried the 'measure' tool in the map display, but it only gives
distance.

I could go and learn more about PostGIS for sending the vector data to a
postgres geometry table and figure it out that way... I was hoping to
find a way to do it in GRASS in a matter of minutes, not via a database
and a couple of days/weeks of learning how...

What tool/command should I be using?

regards,
Shane.

Hi,
sth like this can also be of help:

v.db.addcol map=yourVectorMap column=“area_size double precision”
v.to.db map=yourVectorMap type=centroid option=area units=h column=area_size

Regards

On Mon, Jan 30, 2012 at 6:44 PM, Michael Barton <Michael.Barton@asu.edu> wrote:

Use v.report - under the vector/reports menu

Michael


C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Jan 30, 2012, at 10:00 AM, <grass-user-request@lists.osgeo.org> wrote:

Date: Mon, 30 Jan 2012 17:52:40 +1000
From: Shane Litherland <litherland-farm@bigpond.com>
Subject: [GRASS-user] how to report/measure a vector area?
To: grass-user@lists.osgeo.org
Message-ID: 1327909960.6375.15.camel@Lacebark
Content-Type: text/plain; charset=“UTF-8”

Hi all,

I’m lost. I have looked around in GRASS for how to report the area (e.g.
in hectares) for a vector map that, yes, has area (i.e. centroids and
boundaries).

I cannot find a way to do this. A bit of web searching, even gave some
suggestions this basic facility may not be available in GRASS?? surely
there’s something tucked away to do it?

I’m sure I’ve done something in the past to view vector area data,
though it may have been area data that was already in a table. When I
use the query tool in map display, it tells me ‘nothing’. Seems that is
because my vector is not connected to an attribute table. For the
purpose of my exercise I did not need cats for the boundaries/centroids
so I didn’t bother with a table connection either. Maybe this is where
I’ve gone wrong?

I did try vector to raster to try and report on how many raster
cells/area… no luck there either.

I also tried the ‘measure’ tool in the map display, but it only gives
distance.

I could go and learn more about PostGIS for sending the vector data to a
postgres geometry table and figure it out that way… I was hoping to
find a way to do it in GRASS in a matter of minutes, not via a database
and a couple of days/weeks of learning how…

What tool/command should I be using?

regards,
Shane.


grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

Ismael G.
Ingeniero de Caminos (UPM). Ingénieur des Ponts et Chaussées (ENPC).
PhD researcher @ Urban & Land Planning Department @ ETSICCPM UPM www.caminos.upm.es +34 91 336 67 83

Yes. The cool (and sometimes confusing) thing about GRASS is that often there are several ways of getting the result you want.

Michael


C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)

www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Jan 30, 2012, at 12:32 PM, Ismael Gómez wrote:

Hi,
sth like this can also be of help:

v.db.addcol map=yourVectorMap column=“area_size double precision”
v.to.db map=yourVectorMap type=centroid option=area units=h column=area_size

Regards

On Mon, Jan 30, 2012 at 6:44 PM, Michael Barton <Michael.Barton@asu.edu> wrote:

Use v.report - under the vector/reports menu

Michael


C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Jan 30, 2012, at 10:00 AM, <grass-user-request@lists.osgeo.org> wrote:

Date: Mon, 30 Jan 2012 17:52:40 +1000
From: Shane Litherland <litherland-farm@bigpond.com>
Subject: [GRASS-user] how to report/measure a vector area?
To: grass-user@lists.osgeo.org
Message-ID: 1327909960.6375.15.camel@Lacebark
Content-Type: text/plain; charset=“UTF-8”

Hi all,

I’m lost. I have looked around in GRASS for how to report the area (e.g.
in hectares) for a vector map that, yes, has area (i.e. centroids and
boundaries).

I cannot find a way to do this. A bit of web searching, even gave some
suggestions this basic facility may not be available in GRASS?? surely
there’s something tucked away to do it?

I’m sure I’ve done something in the past to view vector area data,
though it may have been area data that was already in a table. When I
use the query tool in map display, it tells me ‘nothing’. Seems that is
because my vector is not connected to an attribute table. For the
purpose of my exercise I did not need cats for the boundaries/centroids
so I didn’t bother with a table connection either. Maybe this is where
I’ve gone wrong?

I did try vector to raster to try and report on how many raster
cells/area… no luck there either.

I also tried the ‘measure’ tool in the map display, but it only gives
distance.

I could go and learn more about PostGIS for sending the vector data to a
postgres geometry table and figure it out that way… I was hoping to
find a way to do it in GRASS in a matter of minutes, not via a database
and a couple of days/weeks of learning how…

What tool/command should I be using?

regards,
Shane.


grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

Ismael G.
Ingeniero de Caminos (UPM). Ingénieur des Ponts et Chaussées (ENPC).
PhD researcher @ Urban & Land Planning Department @ ETSICCPM UPM www.caminos.upm.es +34 91 336 67 83