[GRASS-user] v.clean error threshold under 2 meters

[Pierluigi De Rosa]

Dear all, 

I'm running under an XY location (uprojected). 
Could be this the problem? 
We are using a local zero not linked to any reference system. 
Here the output: 

g.proj -w 
XY location (unprojected) 

g.region -p 
projection: 0 (x,y) 
zone: 0 
north: 1 
south: 0 
west: 0 
east: 1 
nsres: 0.0001 
ewres: 0.0001 
rows: 10000 
cols: 10000 
cells: 100000000 

This is the output of v.clean 
v.clean input=rill_800_parcellaB_polyline at pierluigi output=rill_800_parcellaB_prune tool=prune threshold=0.1 
-------------------------------------------------- 
Tool: Threshold 
Prune: 0.1 
-------------------------------------------------- 
... 
-------------------------------------------------- 
Tool: Prune lines/boundaries 
0 vertices from input 11742 (vertices of given type) removed, i.e. 0.00 % 
-------------------------------------------------- 

Thanks 

Pierluigi 

----- Messaggio originale -----

Da: "Markus Neteler" <neteler at osgeo.org> 
A: "Pierluigi De Rosa" <pierluigi.derosa at gfosservices.it> 
Cc: "GRASS user list" <grass-user at lists.osgeo.org> 
Inviato: Lunedì, 6 aprile 2015 21:28:14 
Oggetto: Re: [GRASS-user] v.clean error threshold under 2 meters 

Hi Pierluigi, 

On Thu, Apr 2, 2015 at 11:34 AM, Pierluigi De Rosa 
<pierluigi.derosa at gfosservices.it> wrote: 
> Dear all, 
> 
> I have a unusual system unit. 

Please tell us which :-) 

> I'm working on a parcel unit for rill 
> analysis. I'm able to extract the network and I would prune a bit the 
> resulting output. 
> All the parcel I'm studying is 10 meters wide and 22 meters long, the mean 
> average distance between the streams is about 1-2 centimetres. I need to 
> remove nodes in a threshold of 0.005 meters (half centimetre) but I'm having 
> problem assigning such threshold to v.clean 
> I'm running GRASS7. 
> If I use these thresholds ( 0.005, 0.01,1,) no points are removed. 
> The first valid working threshold is 2 meters. 
> 
> Maybe v.clean does not accept value under 1 meter or I'm doing something 
> wrong? 

v.clean should accept "any" value (and we have used GRASS GIS with 
microscope data in the nanometer scale). 

Could you post the output of 

g.region -p 
g.proj -w 
? 

best 
Markus 

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