[GRASS5] [bug #3910] (grass) v.buffer - creating buffer areas does not work

GRASS GIS GRASS GIS developer
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1

this bug's URL: http://intevation.de/rt/webrt?serial_num=3910
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Subject: v.buffer - creating buffer areas does not work

Platform: GNU/Linux/i386
grass obtained from: CVS
grass binary for platform: Downloaded precompiled Binaries
GRASS Version: 6.1.cvs

Hi,
I tried to create a new area boundary around a line theme (where the lines describe a closed ring). Thought it would be easy to do it like this:

v.buffer in=ausschnitt out=buff_ausschnitt bufcol=gesamtbr type=boundary

But GRASS won't create a new theme (there is result theme "buff_ausschnitt", but it is not possible to open it: QGIS "The layer is no valid layer and cannot be added to the map").
After that, I tried to first create a line buffer theme (works fine) and then convert it to a area boundary theme using v.type. However, the new area boundary theme does not have the shape of the line buffer theme. The new created polygon fills out the space inside the ring.

Regards,
Wolfgang

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2

this bug's URL: http://intevation.de/rt/webrt?serial_num=3910
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Subject: v.buffer - creating buffer areas does not work

..

GRASS Version: 6.1.cvs

..

I tried to create a new area boundary around a line theme (where the
lines describe a closed ring). Thought it would be easy to do it like
this:

v.buffer in=ausschnitt out=buff_ausschnitt bufcol=gesamtbr
type=boundary

But GRASS won't create a new theme (there is result theme
"buff_ausschnitt", but it is not possible to open it: QGIS "The layer
is no valid layer and cannot be added to the map").

If there are no boundary features in the input map, the buffering around
boundaries will be empty. Use v.type to convert.

Remember that lines will be buffered both sides, areas (boundaries) only
outside themseleves.

After that, I tried to first create a line buffer theme (works fine)
and then convert it to a area boundary theme using v.type. However,
the new area boundary theme does not have the shape of the line buffer
theme. The new created polygon fills out the space inside the ring.

d.vect cat=1-999999

will draw only real features (not fill holes).

I think you need to run v.type before v.buffer.

Hamish