Hi Alex-
Thanks for the response, which helped me get a step closer to what I want.
Now that I have removed the extensions from the files as you suggest, I am
able to process one file, but am not able to process an entire directory of
files. Upon running a loop over all files in the directory, it only
processes the first file and returns the calculated values (slope in my
case). However, there are 62 files in my directory and I'm at a loss for
why I can't process all of them in my loop. Sample code follows:
library(RSAGA)
wd.in<-"C:\\my.dir"
setwd(wd.in)
env<-rsaga.env(path="C:\\programs\\saga_vc", cmd="saga_cmd.exe")
asc.files<-dir(wd.in, pattern='.asc$')
asc.files<-substr(basename(asc.files), 1, nchar(basename(asc.files)) - 4)
> asc.files
[1] "tmp1_220E-15N2005-03-02" "tmp10_220E-15N2005-05-13"
"tmp100_220E-15N2007-05-13" "tmp101_220E-15N2007-05-21"
"tmp102_220E-15N2007-05-29"
for (i in length(asc.files[i])) {
rsaga.esri.wrapper(fun=rsaga.slope, in.dem=asc.files[i],
method="maxslope", in.esri=T, out.esri=T, clean.up=T,
out.slope=c(paste("SLOPE",asc.files[i],sep="")), env=env, esri.workspace=
wd.in, format="ascii", georef="corner", prec=3)
}
This loop works, but only processes one file and stops. My directory now
includes the following files:
[1] "SLOPEtmp1_220E-15N2005-03-02" "tmp1_220E-15N2005-03-02"
"tmp10_220E-15N2005-05-13" "tmp100_220E-15N2007-05-13"
Thanks again for suggestions on how to process the whole directory.
Tim Sippel
On Mon, Mar 2, 2009 at 4:43 AM, Alexander Brenning <brenn...@uwaterloo.ca>wrote:
> Hi Tim,
>
> the rsaga.esri.wrapper currently expects the in.* and out.* arguments (with
> the ASCII/float ESRI grids) to have NO file extension - the file extension
> to be used for all ESRI grids can be given by the esri.extension argument;
> it currently defaults to ".asc" when format="ascii" and to ".flt" when
> format="binary". (Sorry that the help file is not explicit enough regarding
> the file extensions; will add this to the next update.)
>
> Two more remarks on your code:
>
> > read.ascii.grid(i)
> This simply reads the grid but does nothing else - redundant.
>
> > prec=1
> Slope is calculated in radians (see ?rsaga.slope). So with a 0.1 radian
> increment (the smallest increment that can be represented with prec=1
> digits) you get 0.1 * 180 / pi = 5.7 degree increments on the degree scale -
> you probably want to haver a finer discretization. I would recommend prec=3
> in the case of slope (and probably prec=6 or 7 for curvature attributes).
>
> I hope this helps.
>
> Cheers
> Alex
>
>
> Tim Sippel wrote:
>
>> I'm using RSAGA (version 0.9-4) to calculate rate of change (slope) on a
>> series of .asc files. I'm getting en error message saying it can't open
>> the
>> grid. My code follows:
>>
>> library(RSAGA)
>> # data directory containing my .asc files to calculate slope on
>> wd.in<-"C:\\my.data.dir"
>> setwd(wd.in)
>> env<-rsaga.env(path="C:\\programs\\saga_vc", cmd="saga_cmd.exe")
>> asc.list<-dir(wd.in, pattern='.asc$')
>> for (i in asc.list) {
>> read.ascii.grid(i)
>> rsaga.esri.wrapper(fun=rsaga.slope, in.dem=i, method="maxslope",
>> in.esri=T, out.esri=T, clean.up=T,
>> out.slope=c(paste("SLOPE",as.character(i),sep="")), env=env,
>> esri.workspace=wd.in, format="ascii", georef="corner", prec=1)
>> }
>>
>> Here are some of the data files in my directory from my asc.list object
>> above:
>>
>> asc.list
>> [1] "tmp1_220E-15N2005-03-02.asc" "tmp10_220E-15N2005-05-13.asc"
>> "tmp100_220E-15N2007-05-13.asc" "tmp101_220E-15N2007-05-21.asc"
>> [5] "tmp102_220E-15N2007-05-29.asc" "tmp103_220E-15N2007-06-06.asc"
>> "tmp104_220E-15N2007-06-14.asc" "tmp105_220E-15N2007-06-22.asc"
>>
>> The error I'm getting is below:
>>
>> SAGA CMD 2.0.3
>> library path: C:\programs\saga_vc/modules
>> library name: ta_morphometry
>> module name : Local Morphometry
>> author : (c) 2001 by O.Conrad
>> Load grid: tmp1_220E-15N2005-03-02.asc...
>> failed
>> error: Grid file could not be opened.
>> error: input file [tmp1_220E-15N2005-03-02.asc]
>> error: executing module [Local Morphometry]
>>
>> Not sure what I've done wrong in calling in the grid files and would
>> appreciate advice.
>>
>> Best regards,
>>
>> Tim Sippel
>> University of Auckland
>>
>> [[alternative HTML version deleted]]
>>
>> _______________________________________________
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>> R-sig-Geo@stat.math.ethz.ch
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>>
>>
> --
> Alexander Brenning
> brenn...@uwaterloo.ca - T +1-519-888-4567 ext 35783
> Department of Geography and Environmental Management
> University of Waterloo
> 200 University Ave. W - Waterloo, ON - Canada N2L 3G1
> http://www.fes.uwaterloo.ca/geography/faculty/brenning/
>
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