I'm a very new GRASS user, and I hope this matter hasn't been discussed many times before. (And I hope this message doesn't arrive to you many times: I've tried sending it two times so far, and with no success. Now I'm trying from my work address, let's see if this helps.)
I'm using GRASS 6.3 and I'm having some trouble with the i.class module. I've learned to go around the first problem, but not the other one, and it has halted my work now.
The first problem arises if I try to start i.class by just typing "i.class" into the command line. I am queried for the raster map I want to obtain the signatures from, and then the image group, and so far all is well. But when I'm queried for the image subgroup, the subgroup I give is never OK, and if I type "list" for the available subgroups, there never seem to be any subgroups in my image group. I have created the appropriate image groups and subgroups using i.group, and have used them succesfully with other
applications, so the subgroup should be there. However, the i.class doesn't see it, at least not when I start it that way.
I can go around this problem, if I specify the group and subgroup already when calling i.class, i.e. if I type
i.class map="name" group="name" subgroup="name" outsig="name"
Then the graphic window opens up nicely and I can specify the training regions. But then another trouble comes along.
After I've selected and saved and named all my training regions, and exited i.class, all seems to be OK, and signature file is saved. But when I start i.maxlik and try to use the created signature file for classifying, I get the error message:
ERROR: Can't read signature file [signature].
When I run i.maxlik with a signature file created by i.cluster, I don't have any problems. Why can't I open the signature I've created with i.class? I can see the signature file listed under /subgroup/sig/ so it has been created, it just can't be accessed by i.maxlik. I've tried again and again, I've tried saving the signature with different names etc. and I always get the same error message.
I would greatly appreciate any help in this matter! Thank you so much in advance!
Yours,
Paula Sankelo
PS: I love GRASS, I'm so happy I found it! This is the first serious trouble I've run into so far.
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