[Qgis-user] problems making grass training map via qgis

[Samantha Goodchild-Brown]

Mischa

I am working on those commands but In Linux side I have got the training 
map to raster format with all visible.
More issues I overcame (for students benefit) is:
I imported a shape file made in Qgis with the RGB column and label 
column. To get this to work I had to select 'command dialog' button in 
'import vector data' box and not just use' ivd' box gui.
In the' import vector data' gui I ticked 'override dataset projection 
(use locations projection)' and 'limit import to the currect region' and 
made no other changes in the command dialog box except to repeat input 
and output dataset names!
Now v.to rast works but it doesn't allow out to specify the attribute 
columns - looks greyed out, so you just type them as you know them, it 
works!

In windows grass I imported the same shp file, in the same way, 
successfully. (this using grass not grass plugin in QGIS)  In the 
v.to.rast I can specify / select the attribute columns but when I 'run' 
it, I get the following:

(Fri Aug 24 12:46:44 2012)
v.to.rast input=qgis_lclu_trainingmap2 at 3420new output=trainingmap_raster 
column=cat_ rgbcolumn=RGB labelcolumn=label
Loading data...
Reading areas...
Reading features...
Writing raster map...
Converted areas: 6 of 6
Converted points/lines: 0 of 0
v.to.rast complete.
(Fri Aug 24 12:46:45 2012) Command finished (0 sec)

Which one would think means everything is fine but now can see no data - 
the entire dataset created is the same colour (white).

Is the data most likely still there and just not displaying correctly, 
or has some of the attribute info all been lost and it all does have the 
same value?

On 2012/08/16 18:48, Micha Silver wrote:
> On 16/08/2012 18:11, Samantha Goodchild-Brown wrote:
>> Thank you
>>
>> In my frustration I have reverted to linux version which has proved 
>> useful - seeing more messages is helpful.
>> Mischa, your tip of g.region vect as well as finding reference to 
>> v.in.region has proved helpful. This is likely to be my critical mistake.
>> In using the 'grass interface' I have again hit the RRR:GGG:BBB field 
>> request (as I did with windows).
>> It is very frustrating to find this now again when I can find no 
>> other reference to it anywhere (not even in tuts cautioning to make 
>> label column).
>> Is it absolutely neccessary to go into this at this point (go all the 
>> way back and begin again) or is there a way to 'bypass' it?
>> Or some quick shortcut?
>>
>
> Can you copy into an email the commands you are running, and the 
> results (errors) you are getting?
> If you're using the Linux terminal, then copy/paste the commands and 
> output, and post here.
>
>>
>>
>> Sam
>>
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>> On 2012/08/15 19:52, Paolo Cavallini wrote:
>>> Or use OTB, also through sextante.
>>> --
>>> http://faunalia.eu/pc
>>> Sent from mobile, sorry for being short
>>>
>>> richard burcher <drownedfrog at gmail.com> ha scritto:
>>>
>>>     Another option is to create training polygons&  use [1] SAGA for the
>>>     supervised classification (either standalone or through the Sextante
>>>     plugin). I've recently gone this way for a maximum likelihood
>>>     classification.
>>>
>>>     [1]http://www.saga-gis.org/en/index.html
>>>
>>>     Cheers,
>>>
>>>     Richard
>>>
>>>
>>>
>>>     --
>>>     View this message in context:http://osgeo-org.1560.n6.nabble.com/problems-making-grass-training-map-via-qgis-tp4995324p4995387.html
>>>     Sent from the Quantum GIS - User mailing list archive atNabble.com  <http://Nabble.com>.
>>>     ------------------------------------------------------------------------
>>>
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>>
>>
>>
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