[GRASS5] [bug #3188] (grass) v.net.iso: some roads cost, others distance: sorry

[Radim Blazek]

Just for others, so that they don't get wrong impression.
If you need to use costs you can calculate them in the database (use 
postgres). In this special case something like:
v.to.db option=length
echo "update my set cost = length where costs is null" | db.execute.

Radim


Request Tracker wrote:
> this bug's URL: http://intevation.de/rt/webrt?serial_num=3188
> -------------------------------------------------------------------------
> 
> v.net.iso afcolumn=cost allows us to use a cost instead of a distance
> for segments.
> 
> OK, what if on some of my roads I want to use cost, and some I want to
> use distance?
> 
> Surprise surprise, nope. It's either all cost, all distance, or close
> the road with -1.
> 
> Forget about DELETE FROM table WHERE cat =
> road_I_want_measured_by_distance, v.net.iso will go nuts.
> 
> OK, then what are you going to set its value to in the table, -1? 0?
> -1 is for closed roads. 0 is for 0 cost roads.
> 
> Nope. "The software engineers never considered this possibility."!!!
> 
> The solution for now would be: if the row is not found in the table,
> then measure distance. Better would be -2: use distance.
> 
> 
> --- Headers Follow ---
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> Subject: v.net.iso: some roads cost, others distance: sorry
> From: Dan Jacobson <jidanni at jidanni.org>
> Date: Wed, 27 Apr 2005 05:00:27 +0800
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