Trying to convert lines to polygons

The areas you create are not labelled (means that v.to.rast will give
you an empty file). Snapping doesn't help. Labelling is done via the
dig_att file : an entry for each area or line to be labelled made as
following for an area :

A xxxxxx yyyyyy nn

A means area (L for line), xxxxx and yyyyyy are the coordinates of the
label point (inside the area), and nn is the area number (> 0).

Try to use v.digit after running v.support. There is some command
to show unlabelled areas. You can label each area interactively.
If some areas cannot be labelled, look at the nodes around them (and
zoom)
If there is some green dots, that's mean that a line doesn't match
any other. You can snap manualy lines together, solving the unclosed
polygon problem. After that rerun v.support to label area, and

v.to.rast

will work.

If you have some labels in dxf, you can import them in the dig_att file
with respect to the format showed above (v.digit is sometimes boring

:slight_smile:
Well, in order to export the map into a raster format it would be a good
solution, but I want to get the areas in the vector format and export
them into a shape file. It doen't matter if the dbf file is empty, I
only want the map.
In the other hand, GRASS detect the lines not owned by areas (in v.digit
I can see these opened lines, option "o" in the Toolbox), but I cannot
create new areas from v.digit. I've tried to label all the lines of a
not detected area and after that I don't know how to make GRASS to
detect the polygon (v.support doesn't recognize it).
Besides, it would be very boring to create all the missing areas from
v.digit because I am working with big maps...
Can you help me?
Thank you for your time.
Juan Bañuls.

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Hi everybody-

I have problems with i.cluster. I want to perform a unsupervized radio-
metric classification of some passive microwave images. I have success-
fully imported them into GRASS5.0beta. I created a group and a subgroup
containing four of the seven channels - each has *no* NULL or 0 values
in the region set with g.region. There is *no* mask set. g.region
reports:

GRASS 5.0beta > g.region -p
projection: 0 (x,y)
zone: 0
north: 2250000
south: 1800000
east: -100000
west: -550000
nsres: 3125
ewres: 3125
rows: 144
cols: 144

But all I get is:

GRASS 5.0beta > i.cluster group=f13_ndc_9701XX_1200
subgroup=f13_ndc_9701XX_1200 sigfile=f13_ndc_9701XX_1200.txt
classes=4
Reading image ... 100%
ERROR: Not enough non-zero sample data points. Check your current
region
      (and mask)

The "source-images" or in the mapset PERMANENT not in the current
"working" one - does this matter?

Thanks in advance for any hint,

  Stephan

--
------------------------------------------------------------------------

Stephan Eickschen Tel. : +49 (0)251 83-34704
Westfaelische Wilhelms-Universitaet Fax. : +49 (0)251 83-36100
Institute for Geophysics
Research Unit of Physical Glaciology email: eicksch@uni-muenster.de
Corrensstrasse 24
48149 Muenster
Germany
    http://earth.uni-muenster.de/~eicksch/
------------------------------------------------------------------------

Juan Bañuls wrote:

>The areas you create are not labelled (means that v.to.rast will give
>you an empty file). Snapping doesn't help. Labelling is done via the
>dig_att file : an entry for each area or line to be labelled made as
>following for an area :
>
>A xxxxxx yyyyyy nn
>
>A means area (L for line), xxxxx and yyyyyy are the coordinates of the
>label point (inside the area), and nn is the area number (> 0).

[...]

>If you have some labels in dxf, you can import them in the dig_att file
>with respect to the format showed above (v.digit is sometimes boring

Well, in order to export the map into a raster format it would be a good
solution, but I want to get the areas in the vector format and export
them into a shape file. It doen't matter if the dbf file is empty, I
only want the map.
In the other hand, GRASS detect the lines not owned by areas (in v.digit
I can see these opened lines, option "o" in the Toolbox), but I cannot
create new areas from v.digit. I've tried to label all the lines of a
not detected area and after that I don't know how to make GRASS to
detect the polygon (v.support doesn't recognize it).
Besides, it would be very boring to create all the missing areas from
v.digit because I am working with big maps...

If you have only one attribute (number, not string) for each poly,
this number can be the third figure in the dig_att file, and the
two first the coordinates of a point inside the poly.
After cleaning with v.digit, you have to run v.support and verify
that there is no attribute left (v.support doesn't modify dig_att)

After that, you can transform through v.to.rast OR export in shape
format... but why not directly import dxf ? or change from line
to poly in the final software ?

--
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