[GRASS-dev] vector dissolve problems
neteler at itc.it
Sat Nov 11 10:27:30 EST 2006
It tends to drive me crazy...
So: Attached box.asc for Spearfish as test case.
v.in.ascii box.asc out=box format=standard
d.vect box disp=cat
# Here maybe the first problem starts: Do we need also
# the boundaries to be of the cat of the centroid?
# Anyway, can be easily changed in box.asc.
v.extract -d box out=box_diss
# nothing dissolved :-(
- is the test case correct (I suspect not)?
- with a working test case, does it work with 6.2 and 6.3 or
only 6.2 (I suspect 6.2 only)
I used it in September to dissolve VMAP0 gridlines, so
Let's fix this test case and include it into v.extract for
Soeren's test suite.
On Fri, Nov 10, 2006 at 09:36:47PM -0700, Michael Barton wrote:
> Let me know if you get any good tips. We have a similar problem. One of my
> students is trying to turn a series of soil maps in DXF format into soil
> areas. The boundaries cut across soil areas. We've tried v.clean with snap
> to no avail so far. She needs to close a LOT of polygons in order to turn
> them to areas.
> Michael Barton, Professor of Anthropology
> School of Human Evolution & Social Change
> Center for Social Dynamics & Complexity
> Arizona State University
> phone: 480-965-6213
> fax: 480-965-7671
> www: http://www.public.asu.edu/~cmbarton
> > From: Markus Neteler <neteler at itc.it>
> > Date: Fri, 10 Nov 2006 12:31:08 +0100
> > To: GRASS developers list <grass-dev at grass.itc.it>
> > Subject: [GRASS-dev] vector dissolve problems
> > Hi,
> > I try to merge the 100km tiles of the CORINE vector
> > landcover maps which are delivered in SHAPE format.
> > Due to the tiling there are annoying boundaries now
> > when patching the tiles together. I then tried to
> > reclass and dissolve them based on the landuse
> > code to no avail.
> > Procedure:
> > for i in E43N26 E44N26 E45N26 E43N25 E44N25 E45N25
> > do
> > unzip /cdrom/data/clc00/100km$i.zip
> > v.in.ogr 100km$i.shp out=clc2000_$i
> > done
> > v.patch -e `g.mlist type=vect pat="clc2000_*" sep=,` out=clc2000_tn_bl
> > # break tile boundaries:
> > v.clean clc2000_tn_bl out=clc2000_tn_bl_clean tool=break
> > # reclass to landuse code:
> > v.reclass clc2000_tn_bl_clean out=clc2000_tn_bl_recl col=CODE_00
> > # dissolve
> > v.extract -d clc2000_tn_bl_recl out=clc2000_tn_bl_dissolved
> > The resulting map remains essentially unchanged:
> > http://mpa.itc.it/markus/tmp/vect_dissolve_troubles.png
> > Manual removal in v.digit works. But since I have 700 tiles...
> > Any ideas?
> > Markus
Markus Neteler <neteler itc it> http://mpa.itc.it/markus/
ITC-irst - Centro per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
Via Sommarive, 18 - 38050 Povo (Trento), Italy
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