[GRASS-user] i.gensig comment- Signature 1 not positive definite

GRASS GRASS user
1

Greetings

For a few training areas I'm obtaining the following comment (which means that my signature files are created but empty):
Signature 1 not positive definite
What does this means?

Thanks
Antonio

__________ Information from ESET NOD32 Antivirus, version of virus signature database 5647 (20101125) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

2

I had this same error message sometime in the past few weeks, and I can’t remember exactly what I did, but it was one of the following:

  1. Data has to be transformed to 0-255 positive integers
  2. You need to apply a mask to the null values
  3. Possibly your training area is not large enough

This is skirting your question a bit, as I can’t tell you what the error message means. But hopefully you can find your way around the problem with one of the above steps! And, if you figure it out please let me know so I can write it down this time…

Best of luck,
Nick

---------- Forwarded message ----------
From: António Rocha <antonio.rocha@deimos.com.pt>
Date: 2010/11/25
Subject: [GRASS-user] i.gensig comment- Signature 1 not positive definite
To: GRASS user list <grass-user@lists.osgeo.org>

Greetings

For a few training areas I’m obtaining the following comment (which means that my signature files are created but empty):
Signature 1 not positive definite
What does this means?

Thanks
Antonio

__________ Information from ESET NOD32 Antivirus, version of virus signature database 5647 (20101125) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

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