On 1/11/11 5:29 AM, grass-user-requ...@lists.osgeo.org wrote:
Message: 3
Date: Mon, 31 Oct 2011 16:18:40 +0900
From:sgw00...@nifty.com
Subject: [GRASS-user] How to add new columns of number of nodes and
length of line vector ?
To:grass-user@lists.osgeo.org
Message-ID:<jxy3diiyso6qryahrf6yus...@nifty.com>
Content-Type: text/plain; charset=ISO-2022-JP
Hi grass users;
We traced bird migration by marine radar.
By using graphic analyze of radar monitor capture on PC, we had many line
vectors of bird flight.
I would like to add new columns of the number of node and lenght of line vector,
So;
v.db.addcol line_db columns="num_node int"
v.db.addcol line_db columns="length double precision"
After that, to update and fill two columus, what commands do I use ?
I think...can I use SQL query with spatilite...is it right ?
Best
Yasuo shimada ( Japan Weather Association )
Yasuo -
For length:
v.to.db map=line_db option=length units=k column=length
This would put the length of the line into the column, in kilometers. If
you want some other unit, check v.to.db --help to choose the right
parameter.
I don't know how to check the node count - someone else may help there.
Cheers,
Richard
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