[GRASS-user] r.to.vect and then v.clean using tool=rmarea creates polygons instead of holes.

[Moskovitz, Bob]

Hello Grass-Users,
 
I'm having problems with this sequence of commands:
    r.to.vect -s input=lszone output=lszone10 feature=area
    v.clean input=lszone10 output=lszone10_clean tool=rmarea thresh=2800
 
Below is the output.
 
Overlaying lszone and lszone10_clean, I see that there are large holes that have been replaced with polygons.  Is this a bug?
 
Btw, I've tried this with QGIS on Windows XP as well as GRASS 6.4.svn with the same results.
 
Bob
 

======================================================================
r.to.vect -s in=lszone out=lszone10 feature=area
Extracting areas...
 100%
 100%
Building topology for vector map <lszone10>...
Registering primitives...
50074 primitives registered
629002 vertices registered
Building areas...
 100%
27613 areas built
17107 isles built
Attaching islands...
 100%
Attaching centroids...
 100%
Number of nodes: 39568
Number of primitives: 50074
Number of points: 0
Number of lines: 0
Number of boundaries: 33886
Number of centroids: 16188
Number of areas: 27613
Number of isles: 17107
Number of areas without centroid: 11425
r.to.vect complete.
v.clean in=lszone10 out=lszone10_clean tool=rmarea thresh=2800
--------------------------------------------------
Tool: Threshold
Remove small areas: 2.800000e+03
--------------------------------------------------
Copying vector lines...
Rebuilding parts of topology...
Building topology for vector map <lszone10_clean>...
Registering primitives...
50074 primitives registered
629002 vertices registered
Building areas...
 100%
27613 areas built
17107 isles built
Attaching islands...
 100%
Attaching centroids...
 100%
Number of nodes: 39568
Number of primitives: 50074
Number of points: 0
Number of lines: 0
Number of boundaries: 33886
Number of centroids: 16188
Number of areas: 27613
Number of isles: 17107
Number of areas without centroid: 11425
--------------------------------------------------
Tool: Remove small areas
26251 areas of total size 9.34119e+06 removed
--------------------------------------------------
Rebuilding topology for output vector map...
Building topology for vector map <lszone10_clean>...
Registering primitives...
4913 primitives registered
222687 vertices registered
Building areas...
 100%
1362 areas built
1127 isles built
Attaching islands...
 100%
Attaching centroids...
 100%
Number of nodes: 4678
Number of primitives: 4913
Number of points: 0
Number of lines: 0
Number of boundaries: 4185
Number of centroids: 728
Number of areas: 1362
Number of isles: 1127
Number of duplicate centroids: 3
Number of areas without centroid: 637
 

Bob Moskovitz 
Research Analyst I 
Seismic Hazard Zonation Project
California Geological Survey 
http://www.conservation.ca.gov/cgs/shzp<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

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