[GRASS-user] Update of vector table through selections in the map

[Andreas Philipp]

Hi Jonathan,

I think I understand your task. It is relatively close to mine (quickly assign  
height attributes to a huge set of vector lines manually), today I worked 
more on that script "v.digatt" (attached if it works), it is exactly doing 
(if not completely buggy) what you want, if I'm right: define a attribute 
value (say "1" for intersections) and assign that to all points you click at 
in the following, then define the attribute value of "2" for interchanges and 
click on other  points to assign "2" to their records in the table in one 
step for all of them and so on. The script was tested only for lines, but it 
works fine for that and I tied to make it usable also for points.
The selection is done by v.what.vect (extracting the category numbers of all 
objects you have clicked into a list) and the update is done with v.db.update 
for all collected objects (=category numbers in the list) in one step.
Please try it and tell whether it works for you or not.
Cheers,
Andreas


Am Thursday 08 June 2006 22:08 schrieb Jonathan Aguero:
> First thanks to Dylan Beaudette, Andreas Philipp, and Michael Barton for
> their answers but I guess I didn't explain myself clearly, maybe some more
> detail can help.
> I have a point map representing the intersections on centerline roads
> segments derived from the roads segment map (lines) through a several step
> process. Some of this intersections represent at-grade road intersections
> such as stop controlled intersections or signalized intersections while
> some others represent the on and off ramps in an interchange. I need to
> classify the elements in these two categories, intersections and
> interchanges. The only way to really distinguish between these two types is
> by visual inspection of the segments map and corresponding intersections
> map. So I was looking for a way of selecting several points though out the
> mouse click on the screen and then assigning a value of the attribute for
> all the selected points at the same time. This cannot be accomplished by
> database commands like v.db.update or update/where.
>
> Jonathan Aguero Valverde
>
> -----Original Message-----
> From: Michael Barton [mailto:Michael.Barton at asu.edu]
> Sent: Tuesday, June 06, 2006 12:31 AM
> To: Jonathan Aguero; grassuser at grass.itc.it
> Subject: Re: [GRASS-user] Update of vector table through selections in the
> map
>
> Use v.db.update (in the database menu)
>
> Michael
> __________________________________________
> Michael Barton, Professor of Anthropology
> School of Human Evolution & Social Change
> Center for Social Dynamics & Complexity
> Arizona State University
>
> phone: 480-965-6213
> fax: 480-965-7671
> www: http://www.public.asu.edu/~cmbarton
>
>
>
>
> From: Jonathan Aguero <jua130 at psu.edu>
> Date: Mon, 5 Jun 2006 17:11:37 -0400
> To: <grassuser at grass.itc.it>
> Subject: [GRASS-user] Update of vector table through selections in the map
>
> Dear List,
> I am trying to update the value of several records in a vector table
> simultaneously. The elements to be updated need to be selected in the map.
> I know you can update the values one by one with v.digit or using
> qgis/GRASS but I want to update several each time, something like the
> ³calculate values² in the table using ARC-GIS.
> PD: I am using pgsql for the tables.
> Any idea is welcome, thanks!
>
> Jonathan Aguero Valverde
> Research Assistant and Ph.D. Candidate
> Pennsylvania State University
> The Pennsylvania Transportation Institute
> 201 Transportation Research Building
> University Park, PA 16802
> www.personal.psu.edu/jua130
>
>
>
>
>
>
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