[GRASS-user] Interactively Adding Polygon Attributes to, Centroid

Richard Chirgwin rchirgwin at ozemail.com.au
Sun Oct 14 14:45:04 PDT 2012

On 11/10/12 6:00 AM, grass-user-request at lists.osgeo.org wrote:
> Message: 9
> Date: Wed, 10 Oct 2012 07:52:41 -0700 (PDT)
> From: Rich Shepard<rshepard at appl-ecosys.com>
> To:grass-user at lists.osgeo.org
> Subject: [GRASS-user] Interactively Adding Polygon Attributes to
> 	Centroid
> Message-ID:
> 	<alpine.LNX.2.00.1210100747230.21088 at salmo.appl-ecosys.com>
> Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII
>     A vector map of townships and ranges (part of the US Public Land Survey
> System, PLSS) was poorly digitized. Some of the polygons lack attributes and
> labels. They have a category number when I click on the centroid, but
> there's no row in the associated attribute table for that polygon.
>     I do not see a way to add the row to the displayed attribute table; nor
> does it appear that v.category will allow me to add this information
> interactively to those specific polygons that are lacking.
>     If there is a module or way of using the display (in editing mode,
> perhaps?) I would appreciate learning how to do this task.
> Rich
Rich -

So as to preserve the info you already have, why not add a second table 
to the map, ie
v.db.addtable layer=2 etc?

This should have rows for everything that's got categories.

You could then create a copy of the old map, and use v.distance to 
populate the new table with the information you already have.

Then you can fill in the blanks (that is, centroids with rows in the 
table but no information associated with them), however is most 
efficient to you.

Richard Chirgwin

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