[R-sig-Geo] decimals in NA value using raster::writeRaster with .ascii format

[Zack Holden]

Thanks for getting back to me Jonathan.

In reality, I am creating the files from an existing DEM. However, I
get the same behavior regardless of whether I generate the file in R
(as with my example code) or with actual data.
I have since tested on 4 machines. One windows machine with an older
version of R successfully generates the desired ascii file without the
decimals. The other 3 computers (Linux and windows machines) add the
decimals. As a workaround, I've tried using -Inf as my NAflag. This
eliminates the decimals, but results in a large string of white space
in front of the first row of data. These still cause problems for
PCraster (the next step in the processing chain).

I'm still stumped.

Thanks again,
Zack


On Thu, Apr 10, 2014 at 4:22 PM, Jonathan Greenberg <jgrn at illinois.edu> wrote:
> Zack:
>
> Are you creating the files from within R, or are you just trying to
> convert an existing file?  If the latter, can you make one of those
> files available (e.g. via google drive or dropbox or something like
> that)?
>
> --j
>
> On Thu, Apr 10, 2014 at 3:06 PM, Zack Holden <zaholdenfs at gmail.com> wrote:
>> Dear list,
>>
>> I am creating ascii files as inputs to the PCraster software (no other
>> gdal format is allowed). When I write my ascii file using
>> raster::writeRaster, the first cell of every raster that I write has a
>> large number of decimal values appended to it. This causes errors
>> later in the model workflow.
>>
>> This also happens to the first NA value in the file, so that all NA
>> values in the file are e.g. -9999 except the first cell. which appears
>> as: -9999.00000000000
>>
>> Can anyone suggest a method for ensuring that all of my NA values are
>> identical and with no trailing decimals?
>>
>> A small reproducible example follows. Any help or suggestions is appreciated.
>>
>> Thanks,
>> Zack
>>
>> ##################
>> # start code
>> require(raster)
>> r <- raster(nrows=2, ncols=2, xmn=0, xmx=2, ymn=0, ymx=2)
>> r <- setValues(r, seq(1:ncell(r)))
>> rexpand <- extend(r, c(2,2))
>> NAvalue(rexpand) <- -9999
>>
>> temp.dir <- "/home/zholden/"
>> writeRaster(rexpand, file=paste(temp.dir, "testraster.asc",sep=""),
>> NAflag=-9999, dataType="INT2U", overwrite=T)
>> # end code
>> ##################
>>
>> # opening in a text editor reveals trailing decimals in the first NA value.
>> system(paste("gedit ", temp.dir, "testraster.asc", sep=""))
>>
>> ################################
>>  sessionInfo()
>> R version 3.0.2 (2013-09-25)
>> Platform: x86_64-redhat-linux-gnu (64-bit)
>>
>> locale:
>>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
>> LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
>> LC_MONETARY=en_US.UTF-8
>>  [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C
>>                LC_ADDRESS=C               LC_TELEPHONE=C
>> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
>>
>> attached base packages:
>> [1] stats     graphics  grDevices utils     datasets  methods   base
>>
>> other attached packages:
>> [1] rgdal_0.8-16  raster_2.2-12 sp_1.0-14
>>
>> loaded via a namespace (and not attached):
>> [1] grid_3.0.2      lattice_0.20-23 tools_3.0.2
>>
>> _______________________________________________
>> R-sig-Geo mailing list
>> R-sig-Geo at r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>
>
> --
> Jonathan A. Greenberg, PhD
> Assistant Professor
> Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
> Department of Geography and Geographic Information Science
> University of Illinois at Urbana-Champaign
> 259 Computing Applications Building, MC-150
> 605 East Springfield Avenue
> Champaign, IL  61820-6371
> Phone: 217-300-1924
> http://www.geog.illinois.edu/~jgrn/
> AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307, Skype: jgrn3007