[GRASS-user] v.net.iso calculation based on traveling time fails

[Mithoefer]

Dear List,

I use GRASS GIS 7.4 to calculate traveling distances using v.net.iso 
based on OSM data. I used v.clean to basically clean the data.

If I run an analysis based for distances I get an result, but using 
costs in terms of traveling time it fails. I do not get cat values for 
the classes I defined. These are my GRASS GIS queries:

For Distances:
----------------
v.net.iso input=strassen_net output=strassen_net_iso center_cats=1 
costs=1000,2000,5000 --o

For traveling time: the column acost / bcost = values in minutes
----------------
v.net.iso input=strassen_net output=strassen_cost_iso arc_column=acost 
center_cats=1 costs=10,20,30 --o

What could be the problem? The processing log says, that one entry in 
the database for a line could not be found. However, the same network 
works for distances.

Thanks and kind regards,

Klaus