[R-sig-Geo] integer parameter treatment in doGRASS - WAS: spGRASS6 issue

[Rainer M Krug]

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On 07/02/13 11:48, Roger Bivand wrote:
> On Thu, 7 Feb 2013, Rainer M Krug wrote:
> 
> On 06/02/13 13:22, Rainer M Krug wrote:
>>>> On 06/02/13 12:55, Roger Bivand wrote:
>>>>> On Wed, 6 Feb 2013, R.S. Bhalla wrote:
>>>> 
>>>>>> Dear List, I have run into trouble with the execGRASS command copied below and can't 
>>>>>> figure out what I'm doing wrong. It runs fine without the size=11 argument (takes
>>>>>> the default value of 3). Can
>>>> 
>>>>>> storage.mode(11)
>>>>> [1] "double"
>>>>>> is.integer(11)
>>>>> [1] FALSE
>>>>>> is.integer(11L)
>>>>> [1] TRUE
>>>> 
>>>>> Just because it looks like an integer, it doesn't mean it is.
>>>> 
>>>> Hi Roger
>>>> 
>>>> this has bittan many users, including myself, as it is a little aux contraire to R, as
>>>> here 11 is acepted as integer in most circumstances.
>>>> 
>>>> Would it be possible to use a different check for integer e.g.
>>>> 
>>>> if(as.integer(x) == x) then {x <- as.integer(x)} else {ERROR}
>>>> 
>>>> I have the feeling that would be more in line with the treating in R of different
>>>> numerical storage modes.
> 
> Hi Roger,
> 
> To follow up:
> 
> in the function doGRASS, I would suggest to change:
> 
> 
> 
> else if (pmv[i] == "integer") { if (!is.integer(parameters[[i]])) stop(paste("Parameter <",
> names(parameters)[i], "> does not have integer value", sep = "")) }
> 
> 
> to
> 
> else if (pmv[i] == "integer") { if (!(as.integer(parameters[[i]]==parameters[[i]])) { 
> stop(paste("Parameter <", names(parameters)[i], "> does not have integer value", sep = "")) }
> else { parameters[[i]] <- as.integer(parameters[[i]] } }
> 
> which will cause the error message when a not integer *value* has been submitted, irrespective
> of the storage mode. If it is an integer value, the parameter[[i]] wil be stored as an
> integer.
> 
> A side effect would be that even "11" would be accepted, which is actually quite nice.
> 
> 
>> I've commited some changes to the spgrass6 module of the rspatial project on R-forge
>> (revision 1349), but not the conversion of strings to integer or numeric, which I think must
>> be the users' responsibility, as failure is not an error but an NA. Please let me know if
>> this helps. Maybe the statgrass list is a better forum?
> 
>> Roger

Hi Roger

looks fine with me. Conversion from character to numeric is not necessary: agreed.

I cc this to statsgrass for the record and possibly further comments

Thanks,

Rainer



> 
> 
> 
> In addition, One could even add the same construct to the float test:
> 
> else if (pmv[i] == "float") { if (!(as.numeric(parameters[[i]]==parameters[[i]])) { 
> stop(paste("Parameter <", names(parameters)[i], "> does not have numeric value", sep = "")) }
> else { parameters[[i]] <- as.numeric(parameters[[i]] } }
> 
> 
> I also would suggest to change the error message for float from "not have a float value" to
> "does not have a numeric value" as this is more consistent, as this would be more consistent
> with R terminology.
> 
> Cheers,
> 
> Rainer
> 
> 
>>>> 
>>>> Cheers,
>>>> 
>>>> Rainer
>>>> 
>>>> 
>>>> 
>>>> 
>>>>> Roger
>>>> 
>>>>>> someone please help. Thanks in advance, Ravi
>>>>>> 
>>>>>> Command: execGRASS("r.neighbors", parameters=list(input=patmap, output=n11map, 
>>>>>> method="median", size=11), flags=c("overwrite", "c"))
>>>>>> 
>>>>>> Error: Error in doGRASS(cmd, flags = flags, ..., parameters = parameters, echoCmd = 
>>>>>> echoCmd) : Parameter <size> does not have integer value
>>>>>> 
>>>>>> 
>>>> 
>>>> 
>>>> 
> 
>> 
> 

- -- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys.
(Germany)

Centre of Excellence for Invasion Biology
Stellenbosch University
South Africa

Tel :       +33 - (0)9 53 10 27 44
Cell:       +33 - (0)6 85 62 59 98
Fax :       +33 - (0)9 58 10 27 44

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email:      Rainer at krugs.de

Skype:      RMkrug
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