[GRASS-user] supervised classification "no subgroup files available"

GRASS GRASS user
,
1

Hi grass-users,

I'm trying to run a supervised reclassification for an orthophoto created using r.in.gdal and r.composite.
Before running i.class, i run i.group to create a subgroup which is required by i.class. [The group containing 3 files .red, .green, .blue had been previously created during the import phase].
When I run i.class the interactive screen cannot find the subgroup, it outputs: "no subgroup files available in current mapset". I get the same message also using i.gensig.
I can see the folder and the file REF using "ls" in /Users/silvia/grassdata/location/mapset/group/subgroup/, but somehow GRASS 6.3 cannot.
The result is the i.class exits.

Does anyone know what's going on? How can I create a subgroup that GRASS 6.3 can see?
Thanks

Silvia
----------------------------------------------------------------------------------------
Silvia Simoni PhD
DICA - Department of Civil and Environmental Engineering
Universita' di Trento
via Mesiano 77, 38100 Trento, ITALY
tel. +39 0461 882610
fax. +39 0461 882672
e-mail: silvia.simoni@ing.unitn.it

2

Hi Silvia,

there have been a couple of fixes which probably didn't reach 6.3.0.
Could you try with 6.4.svn instead? There it will work.

Best
Markus

PS: See the list archives for older discussions on this.

On Mon, Sep 1, 2008 at 11:19 AM, Silvia Simoni
<silvia.simoni@ing.unitn.it> wrote:

Hi grass-users,

I'm trying to run a supervised reclassification for an orthophoto created
using r.in.gdal and r.composite.
Before running i.class, i run i.group to create a subgroup which is required
by i.class. [The group containing 3 files .red, .green, .blue had been
previously created during the import phase].
When I run i.class the interactive screen cannot find the subgroup, it
outputs: "no subgroup files available in current mapset". I get the same
message also using i.gensig.
I can see the folder and the file REF using "ls" in
/Users/silvia/grassdata/location/mapset/group/subgroup/, but somehow GRASS
6.3 cannot.
The result is the i.class exits.

Does anyone know what's going on? How can I create a subgroup that GRASS 6.3
can see?
Thanks

Silvia
----------------------------------------------------------------------------------------
Silvia Simoni PhD
DICA - Department of Civil and Environmental Engineering
Universita' di Trento
via Mesiano 77, 38100 Trento, ITALY
tel. +39 0461 882610
fax. +39 0461 882672
e-mail: silvia.simoni@ing.unitn.it

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

--
Open Source Geospatial Foundation
http://www.osgeo.org/
http://www.grassbook.org/

3

Thanks Markus!

I’m now using grass6.4.svn but I still have trouble with the supervised classification process. Now I can run i.class and produce the spectral signature for my map but this file is NOT readable by i.maxlik. I get the following message: Can’t read signature file [signaturefile].

I checked in $MAPSET/group/subgroup/$SUBGROUP/sig/; the signaturefile is there but it only contains 3 lines, as follows:

#comment
single value XXXX

Is this correct? I obtained other signature files from i.cluster which look different from this. It seems to me that i.class doesn’t write the signature file correctly so that i.maxlik is not able to read it.

How can I overcome this problem?

thanks

silvia

On Sep 1, 2008, at 1:30 PM, Markus Neteler wrote:

Hi Silvia,

there have been a couple of fixes which probably didn’t reach 6.3.0.

Could you try with 6.4.svn instead? There it will work.

Best

Markus

PS: See the list archives for older discussions on this.

On Mon, Sep 1, 2008 at 11:19 AM, Silvia Simoni

<silvia.simoni@ing.unitn.it> wrote:

Hi grass-users,

I’m trying to run a supervised reclassification for an orthophoto created

using r.in.gdal and r.composite.

Before running i.class, i run i.group to create a subgroup which is required

by i.class. [The group containing 3 files .red, .green, .blue had been

previously created during the import phase].

When I run i.class the interactive screen cannot find the subgroup, it

outputs: “no subgroup files available in current mapset”. I get the same

message also using i.gensig.

I can see the folder and the file REF using “ls” in

/Users/silvia/grassdata/location/mapset/group/subgroup/, but somehow GRASS

6.3 cannot.

The result is the i.class exits.

Does anyone know what’s going on? How can I create a subgroup that GRASS 6.3

can see?

Thanks

Silvia

Silvia Simoni PhD

DICA - Department of Civil and Environmental Engineering

Universita’ di Trento

via Mesiano 77, 38100 Trento, ITALY

tel. +39 0461 882610

fax. +39 0461 882672

e-mail: silvia.simoni@ing.unitn.it

grass-user mailing list

grass-user@lists.osgeo.org

http://lists.osgeo.org/mailman/listinfo/grass-user

–

Open Source Geospatial Foundation

http://www.osgeo.org/

http://www.grassbook.org/

Silvia Simoni PhD
DICA - Department of Civil and Environmental Engineering
Universita’ di Trento
via Mesiano 77, 38100 Trento, ITALY
tel. +39 0461 882610
fax. +39 0461 882672
e-mail: silvia.simoni@ing.unitn.it

Silvia Simoni PhD
DICA - Department of Civil and Environmental Engineering
Universita’ di Trento
via Mesiano 77, 38100 Trento, ITALY
tel. +39 0461 882610
fax. +39 0461 882672
e-mail: silvia.simoni@ing.unitn.it

4

On Thu, Sep 4, 2008 at 6:24 PM, Silvia Simoni
<silvia.simoni@ing.unitn.it> wrote:

Thanks Markus!

I'm now using grass6.4.svn but I still have trouble with the supervised
classification process. Now I can run i.class and produce the spectral
signature for my map but this file is NOT readable by i.maxlik. I get the
following message: Can't read signature file [signaturefile].

I checked in $MAPSET/group/subgroup/$SUBGROUP/sig/; the signaturefile is
there but it only contains 3 lines, as follows:
#
#comment
single value XXXX

Is this correct? I obtained other signature files from i.cluster which look
different from this. It seems to me that i.class doesn't write the signature
file correctly so that i.maxlik is not able to read it.

It doesn't look good.
But a quick test here didn't show any problem.
Are you sure that
- your training areas are big enough in i.class?
- that you close the training areas with the "complete" button?

Markus

5

Hi Markus,

As to the training area I draw just one, which is fearly small because it's homogeous with rispect to the color I want to sample. I've tried to select other areas in the same section, using the command "draw region", but apparently I'm not allowed to do it.

I always close the training areas with the "complete button".

Here it's the procedure I'm following
1. i.group (to create group A and subgroup rgb)
2. d.mon
3. i.class map=ortophoto_composite group=A subgroup=rgb outsig=test (I can see the file test being created in the folder .../subgroup/$SUBGROUP/sig/; it's now 0 Byte)
4. from the interactive i.class menu, I select "Zoom"; then once the zoomed area is displayed, "Define Region" and "Draw Region". I draw 1 area by points, then I click on "Complete Region" and "Done". As I return to the main menu, I click on "analyse region" -> Signature Menu, "Display matches", "Done". save Signature YES, then I'm prompted for the signature description; finally I Quit from the main menu. Now I can see the file size has increased to 14 Byte. When I edit it, I can see only 3 lines.

I've also tried selecting a much larger area for which the histogramm is smoother that in the previous case, nothing has changed, still 3 lines in the outsig file.

Thanks,

Silvia

On Sep 4, 2008, at 9:52 PM, Markus Neteler wrote:

On Thu, Sep 4, 2008 at 6:24 PM, Silvia Simoni
<silvia.simoni@ing.unitn.it> wrote:

Thanks Markus!

I'm now using grass6.4.svn but I still have trouble with the supervised
classification process. Now I can run i.class and produce the spectral
signature for my map but this file is NOT readable by i.maxlik. I get the
following message: Can't read signature file [signaturefile].

I checked in $MAPSET/group/subgroup/$SUBGROUP/sig/; the signaturefile is
there but it only contains 3 lines, as follows:
#
#comment
single value XXXX

Is this correct? I obtained other signature files from i.cluster which look
different from this. It seems to me that i.class doesn't write the signature
file correctly so that i.maxlik is not able to read it.

It doesn't look good.
But a quick test here didn't show any problem.
Are you sure that
- your training areas are big enough in i.class?
- that you close the training areas with the "complete" button?

Markus

----------------------------------------------------------------------------------------
Silvia Simoni PhD
DICA - Department of Civil and Environmental Engineering
Universita' di Trento
via Mesiano 77, 38100 Trento, ITALY
tel. +39 0461 882610
fax. +39 0461 882672
e-mail: silvia.simoni@ing.unitn.it