[GRASSLIST:2015] Re: input format of v.net.path in GRASS5.7

[Radim Blazek]

On Wednesday 10 December 2003 16:39, Hayashi Shin-ichiro wrote:
> Dear GRASS users:
>
> Thank you very much for your advise, Radim.
>
> I tried
> $ v.net input=walk output=walk_ca
> 1)My question
> 1. does v.net give category for all arc and node?
> 2. Is category number which 1 is arc and 2 is node?
>
> I executed v.net.path. Command worked but didn't make any shortest path.
> $ echo "1 5" |v.net.path input=walk_ca output=walkpath
> Error messege
> WARNING: 54667 points without category.
> WARNING: No point with category 1
> WARNING: No point with category 5
>
> And I tried
> $ v.category in=walk out=walk_ca option=add

But I had written v.category field=2, so try 
v.category in=walk out=walk_ca option=add field=2
echo "1 5" | v.net.path input=walk_ca output=walkpath
Node numbers may be in from <1,54667>, for example
echo "123 45678" | v.net.path input=walk_ca output=walkpath

Note that, you can make more SP at the same time
echo -e "1 2\n3 4" | v.net.path input=walk_ca output=walkpath

> I have same question.
> 1. does v.category give category for all arc and node?
> 2. Is category number which 1 is arc and 2 is node?
>
> Then I executed v.net.path. Command worked but didn't make any shortest
> path. GRASS gives me same error messege.
>
> I execute d.what.rast. But command tell me only infomation about arc.
> 2)My question
> What way can I get infomation about node?
>
> My big question is
> What way can I give category number for node?
>
> Please give me your suggestion.
> Thank you in advance.
> Sincerely yours.

Try to play a bit with 'type' and 'field' options for v.category and d.what.vect
to get idea.

Radim

> >Nodes on the network are identified by category number of points
> >placed exactly on network nodes (ends of lines). If you have lines
> >only in you vector, you can add new points by v.net and assign categories
> >to points by v.category field=2. Then use these categories as input for
> > v.net: echo "1 5" | v.net.path