[GRASS-dev] [bug #4547] (grass) v.clean: break tool for 3D lines resets elevation to 0.00

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this bug's URL: http://intevation.de/rt/webrt?serial_num=4547
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Subject: v.clean: break tool for 3D lines resets elevation to 0.00

Hi,

I have a 3D vector map of boundaries and centroids which started life as a
series of triangular 3D surface faces. They all exist in the same plane with a
constant elevation of ~ -11. I wish to connect them all together and disolve
the common boundaries. (remove diagonal from square feature made up of two
triangles forming a single square polygon from 2*triangles)

but before I can use v.clean tool=rmdupl I need to run tool=break.

v.clean tool=break does its thing, and finds lots of them. Problem is the
output map has (re)set many of the points' z value to 0.0000 and then the
nodes no longer snap together....

If I output an error= map all points have 0.00 elevation. (v.info z-range)


test:
v.category in=grid_faces_clean_polygons1 out=gf2 op=del
v.category in=gf2 out=gf3 op=add type=boundary

v.db.addtable gf3 col="x double, y double, z double"

v.to.db gf3 option=start col=x,y,z

[this is taking a while to run, I'll post the results to the bugtracker tomorrow]

v.univar gf3 col=z
? mean(z) to get propotion of points converted 0 vs number of points in error
map & original.



Hamish


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