[GRASS-dev] formatting expressions for r.mapcalc in GRASS6.4.3

[Helena Mitasova]

Anna,

you are right - it is the commands that include || that give an error,
I finally had time to go through all of the examples in the lab  - all
the other ones work so far. Is this something that can be fixed?

Helena

On Thu, Feb 14, 2013 at 12:25 PM, Anna Kratochvílová
<kratochanna at gmail.com> wrote:
> On Thu, Feb 14, 2013 at 5:41 PM, Helena Mitasova <hmitaso at ncsu.edu> wrote:
>>
>>
>>> The wxGUI command line has its own rules (see shlex.split()
>>> in the Python library documentation).
>>
>> running mapcalc through the wxGUI command line is where the students have problems in winGRASS
>> (but it works on Mac)
>>
>> Helmut - can you please try this commands with data in nc_spm_08
>> just pasting them in command console in wingrass?
>> - I had them originally in double quotes but that did not work for any expression,
>> without quotes this works:
>>
>> g.region rast=landuse96_28m -p
>> r.mapcalc ndvi3=float(lsat7_2002_40-lsat7_2002_30)/float(lsat7_2002_40+lsat7_2002_30)
>>
>> but the students complain that the ones with if statements don't
>> (they say that they tried to put spaces around = and some other modifications but they keep getting syntax error):
>>
>> r.mapcalc urban1_30m=if(landuse96_28m==1,1,0)+if(landuse96_28m==2,2,0)
>> r.mapcalc urban2_30m=if(landuse96_28m==1 || landuse96_28m==2,landuse96_28m,null()
>> g.region rast=elevation -p
>> r.mapcalc MASK=if((elevation<100 && elevation>60) && (landuse96_28m==1 || landuse96_28m==2),1,null())
>
> One problem is caused by the pipe character. It seems that it is taken
> as the end of a command and the rest is evaluated as another command.
> I noticed the same problem when I wanted to execute a command
> (run_command) with option separator = "|" from gui. It's a general
> problem both in grass 6 and 7.
>
> Anna
>
>>
>> so I am trying to figure out how to make r.mapcalc work in wingrass in command console
>> (all of these expressions work if entered through the map calculator GUI)
>>
>> r.mapcalc is one of the most used commands so I think it is important to have it running reliably
>> and it may be just a matter of special instrcutions for wingrass in the manual page,
>>
>> Thank you, Helena
>>
>>>
>>> Map names can be quoted with either single or double quotes, so if the
>>> expression is quoted with double quotes you can quote map names with
>>> single quotes and vice-versa.
>>>
>>> --
>>> Glynn Clements <glynn at gclements.plus.com>
>>> _______________________________________________
>>> grass-dev mailing list
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>>> http://lists.osgeo.org/mailman/listinfo/grass-dev
>>
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-- 
Helena Mitasova
Associate Professor
Department of Marine, Earth and Atmospheric Sciences
North Carolina State University
1125 Jordan Hall
NCSU Box 8208
Raleigh, NC 27695-8208
http://skagit.meas.ncsu.edu/~helena/

email: hmitaso at ncsu.edu
ph: 919-513-1327 (no voicemail)
fax 919 515-7802