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

[Jonathan Greenberg]

Zack:

Hopefully Robert will get back to you (I confirmed it -- it looks like
a bug to me) -- but in the meantime, you might want to try my
gdalUtils package, which uses gdal_translate to convert files.  You
can use one of the many ASCII formats -- you'll want to use parameters
like:
gdal_translate(...,a_nodata=-9999,ot="UInt16",format="...")

You can see the available formats at: http://www.gdal.org/formats_list.html

--j



--

On Thu, Apr 10, 2014 at 5:29 PM, Zack Holden <zaholdenfs at gmail.com> wrote:
> 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



-- 
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